What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Slow Cranking

Aussieflyer

Active Member
Since new the starter motor on the IO390 starts cranking very slowly, often having trouble getting the engine through the first compression. Once through the first compression it commences to spin up normally.

I contacted Sky Tech and they assured me the starter motor is adequate for the job. I purchased a new Odyssey Battery and had it fail three weeks later with a complete cell breakdown. The replacement battery lasted three months before breaking down. The distributor is now arguing that the Odyssey @ 170 Cold Cranking Amps (CCA) is too small and the load used for starting is destroying the battery and I should get a bigger battery and they wont warranty the current battery.

The battery case supplied by Van's will only allow one size battery fit. Perhaps builders should consider manufacturing a battery box that has some flexibility in sizing. The battery shop showed me an AGM battery about a quarter of an inch wider that had over twice the CCA of the Odyssey and asked why we didn't use that battery?

Has anyone tried a Lithium? What would I need to do to install a lithium? Are they safe in the engine space of the 14?

Alan
 
I wired an RV-14A for a buddy, using the Van?s FWF kit. I too believe the single firewall mounted PC-680 as bearly adequate for the job. I recommended a second PC-680, mounted on either side of the firewall and a much revised power distribution system to take advantage of the second battery. He declined, but as he too has had problems with the single battery setup I believe my recommendation to be the right course of action. But then again, I?d never have a single battery ship.

Carl
 
Since new the starter motor on the IO390 starts cranking very slowly, often having trouble getting the engine through the first compression. Once through the first compression it commences to spin up normally.
...

Has anyone tried a Lithium? What would I need to do to install a lithium? Are they safe in the engine space of the 14?

Alan

Search this forum for EarthX. I am very happy with EX900 for over 2 years. It weighs 10 lbs less than the 680 and will spin the prop fast enough to taxi.
 
Skytec 149NL

Alan,
This will be an unpopular opinion, but I offer it with data from owning several airplanes. When my factory new Lycoming IO-390 arrived with the Skytec starter you have I was disappointed. I had used that starter on a few airplanes with many problems. I was well aware of what Skytec would say when I called. They want you to check the voltage under load at the starter. I did all those checks before even calling, my numbers were within the tolerance they require on their website before I called. When I described my starting issues they simply increased the required voltage at the starter above the value on their website and told me to look at my wiring, again.

After owning multiple airplane with that issue I refused. They exchanged the starter you have at a horrible used value and I purchased a Skytec 149NL. It will fit without modification to your airplane. The 149NL documentation will even include instructions on how to grind down unused mounting lugs to make it fit.

CLARIFICATION: Without modification refers to the RV14 and the engine. You will need to grind off some mounting arms on the 149NL in accordance with the Skytec provided documentation. It takes just a few minutes.

My airplane ALWAYS starts easily since I discarded that starter. You can spend a lot of effort looking at your wiring or you can resolve the problem in one day.
 
Last edited:
Alan,
This will be an unpopular opinion, but I offer it with data from owning several airplanes. When my factory new Lycoming IO-390 arrived with the Skytec starter you have I was disappointed. I had used that starter on a few airplanes with many problems. I was well aware of what Skytec would say when I called. They want you to check the voltage under load at the starter. I did all those checks before even calling, my numbers were within the tolerance they require on their website before I called. When I described my starting issues they simply increased the required voltage at the starter above the value on their website and told me to look at my wiring, again.

After owning multiple airplane with that issue I refused. They exchanged the starter you have at a horrible used value and I purchased a Skytec 149NL. It will fit without modification to your airplane. The 149NL documentation will even include instructions on how to grind down unused mounting lugs to make it fit.

My airplane ALWAYS starts easily since I discarded that starter. You can spend a lot of effort looking at your wiring or you can resolve the problem in one day.

Gotta agree with Marvin, if it has the "light weight" permanent magnet starter do yourself a favor and get a good wire wound unit like the B&C or NL.
 
I agree that the NL starter is an upgrade in cranking performance but considering that repeatedly time and again here in the forums I see people troubleshooting with a credit card. It is sad and frustrating to see people spend a lot of money trying to resolve a problem without ever confirming some of the basics. Often times thy even say they have done a bunch of testing but because of lack of experience they didn't get any useful or valid information.
It is for that reason that blindly swapping a part will be the last thing I recommend.
 
Alan,

I suspect, and it proved true with our -10, that the master solenoid health can be an issue. Another -10 owner a bit north of us also had the same issue.

Getting the right solenoid and mounting it the right way up helps with having good contacts and less drop under load. Or so I am told.

Also in winter on cold mornings oil and batteries don't help. We use Phillips 20W-50 and camguard for what it is worth. (Camguard has nothing to do with this other than we use it for hopefully better corrosion protection).
 
Alan,
I'd have to generally agree with the comments so far. The 14 I flew has the NL Starter so it had no issues (230 + hrs) doing the cranking.
If the improved ground cabling (1st cheap option) doesn't fix the problem then a look at the Master solenoid may be the next cheap option ( I supplied the solenoid that David mentioned for the OP) followed by the B&C starter.
FWIW & IMO the B&C products are the bees knees, they have always been the best & my unit is still working after 2400+ hrs without any work done on it despite me asking B&C if I should send it over for a refurbish - after sending pictures of it they said no need to do that & just keep using it. That's confidence on their part :)
Hopefully you get this sorted cost effectively ;)
 
I agree that the NL starter is an upgrade in cranking performance but considering that repeatedly time and again here in the forums I see people troubleshooting with a credit card. It is sad and frustrating to see people spend a lot of money trying to resolve a problem without ever confirming some of the basics. Often times thy even say they have done a bunch of testing but because of lack of experience they didn't get any useful or valid information.
It is for that reason that blindly swapping a part will be the last thing I recommend.

For the most part I agree with the above, however, the starter system is a difficult one to troubleshoot effectively. Trying to crank the engine with a starter that is faulty or "stalled" and take voltage readings is difficult and does not necessarily give valid test results, if you can get any results at all without a meltdown. You can jump the master solenoid to elimate that but the starter and starter sol not so easy.

The big problem with the PM starters is their massive current draw which can easily be upwards of 400 amps, this heavily taxes even the best battery and components in the system. The typical WW starter draws about half that much and therefore the system can tolerate components that are less than perfect, which includes the battery itself. So it takes a "perfect" system to work with the PM starter while the WW units will work fine with something less than "perfect".

The only reason vendors use the PM starter is because it the cheapest and the lightest which make the sales numbers look good.
 
Last edited:
The only reason vendors use the PM starter is because it the cheapest and the lightest which make the sales numbers look good.

Respectfully: There is more to the PM vs wire wound story. The torque per amp is much higher for the equivilant PM design. ref There is inefficiency and power required to energize that field. No free lunch. The engine required torque is what determines the starter output.

The XLT design sounds like it is inferior, just maybe for a different reason than being PM. The magnets could be weak (undersized or poor quality control), maybe it is just a bad design. A voltage test is in order, but if it won't turn it over, poor amps-to-torque conversion can still be the culprit even with a good voltage test. The proof is the stall at first compression. Do the test, test the battery, then hammer (ahh, errr, negotiate) the vendor with data. If the amps are drawn, and the voltage is in range, then the magnets are weak and should be warrantied.

BTW: The first full compression stroke is by far the highest torque demand and is based on the bore-stroke and compression ratio. For the same bore-stroke-compression, a 4 cylinder actually requires higher cycling torque (amps) than a 6. Friction causes the ultimate spinning RPM of a 6 to be lower. All just science, my motor-generator-starter guys had to learn this.
 
Last edited:
Starter Troubles

After reading all the comments will have to agree with Scott. One thing that none of the commenters mention is checking wiring from battery to starter and starter to ground for heat. That was one thing I would do in trouble shooting a problem like this for many electrical problems. The other thing is check for voltage drop at each wire where it connects to a terminal coming from or going to the starter. One bad wire connection to a connector can cause problems but check good if not done at the wire itself.
 
Alan,
One thing I forgot to mention in our discussion yesterday to do as well as the grounding cable (also mentioned by EXflyer) is to use internal star washers on all the ground & power connections ie cables & solenoids;)
 
What sort of a prop are you using.
I use the same battery in an RV4 with aluminium prop and a Corby starlet with a wooden prop and Jabiru 4 cylinder motor. It is far harder to crank the Jab than the Lycoming with a heavier prop.
 
Sky-Tec (now part of Hartzell Engine Technologies) has a number of models:

http://skytec.aero/product/lycoming-aircraft-starters/

The "NL" series are in line (note the location of the solenoid).

Lycoming_NL.jpg


Van's provisioned the RV-14 for the 149-12LS (right hand rotation, external mounted solenoid on the left side). 149 is for the number of ring gear teeth. 12 is for the voltage.

Lycoming_PM.jpg
 
Ok, dumb question. What is a NL starter? Is that a brand or type?

Rob,
A Skytec 149NL is the middle option in the picture below, it is not a permanent magnet (PM) starter much like the B&C products. I think Skytec was sold a few years ago, but the NL below is the same unit.

Although I have an aversion to disagreeing with the more qualified poster in this thread. I believe the PM starters are marginal. A non PM starter requires less of your wiring and battery making them more tolerant over time.

NOTE: I did all the wire, solenoid, and load checks mentioned by many posters above and everything met and exceeded the requirements of the Skytec trouble shooting guide. Like I said above, a marginal product, it can work. The non PM units I have used, even those produced by the same company, have been flawless.

P.S. - B&C makes some really nice units also, I merely happen to know the 149NL will fit a -14 without modification.
4tn8uh.jpg
 
Last edited:
I had a 149PM with an IO-540 on the RV10, and a 149LS I believe that came with the IO-390 on the RV-14. The IO-540 had often had a hard time getting the first blade to turn. The RV-14 actually was doing ok in stock config. BUT, I decided to swap both of them for the NL starter and couldn't be happier. It was a very easy swap, the starter fit both planes without issue (you grind a lug off for the RV-14 to clear the intake), and they both work perfectly for me. I figure it's better to have identical components on both airplanes, because you can swap parts if you ever need to. That happened to me as one of my NL starters had a bad internal connection and failed at 1.25 hours, and I needed that plane. I swapped starters, did the flight, and they sent me a brand new replacement free of charge which has been going strong.

I would say that likely there's a wiring or connection issue, because the stock system works fine with the stock battery and everything else. BUT, if you are going to tear into it, and you question the starter, swap out to the NL and you at least have one that you know will swing it fine.

I should note that the NL, by tech specs, actually spins slightly slower than the others, but not very noticeably.
 
Starter/battery/solenoids

I had similar issues when I bought my RV-4. It has an AEIO-360 and a Hartzell constant speed prop. It was woefully inadequate during start and sometimes it would barely go past a compression stroke. Had constant starting issues and troubleshooting didn't find any obvious issues. Replaced the master & starter solenoids and noticed a much better attitude toward starting but still not a robust start. The big jump was when I removed the Skytec lightweight starter and installed a 149NL starter. Now that was a huge difference and the engine was fairly easy to start with the standard Concord aircraft battery.

After lots of discussion with friends & a couple mechanics I switched the battery to an EarthX ETX 900. The new battery combined with the NL starter spins the prop so fast on start that I barely turn the key and the engine starts.

So the starter was the biggest culprit and the EarthX battery has contributed immensely to super easy starts- cold or hot. Those lightweight starters are probably OK for 320s & FP props but not for the bigger motors & C/S props. 'Mileage may vary' and each engine has it's own personality but those lightweight starters are just not very stout. I sent the lightweight starter to Skytec twice and they were great about rebuilding/replacing so kudos to them for great customer support. Just not a fan of the lightweight models.
 
FWIW

Skytec starter
Odyssey PC-680
Odyssey 12 amp ext charger for maintaining
All OEM from Vans or Lycoming

First flight May 2017

Always rapid cranking quick starting, including when I messed up a hot start flooding the engine requiring a 3 mins rest before start.

Built as per plans. I am curious why some have issues.

R
 
Because of the comments about the Sly Tech starters, I just ordered the IO390 engine from van's. I specifically ask if I could have a B&C starter installed instead of the SkyTech. The answer was yes. I was to call B&C order the starter and send it to Lycoming and they would install the starter.

I called B&C and was told that the B&C will not fit the Horizontal Fuel Flow application. So I could not exchange the two starters. They do not make one that will fit.

I thought I would share this information with the group.
Now I do not know about the Sky Tech 149NL. That might be a possibility.
 
Many of us have installed the 149NL with Horizontal injection with no problem and I personally like it better than the lightweight. Spins nicely.
 
After reading all the comments will have to agree with Scott. One thing that none of the commenters mention is checking wiring from battery to starter and starter to ground for heat. That was one thing I would do in trouble shooting a problem like this for many electrical problems. The other thing is check for voltage drop at each wire where it connects to a terminal coming from or going to the starter. One bad wire connection to a connector can cause problems but check good if not done at the wire itself.

Gotta agree with this and Scott?s post as well. I was taught long ago how to put a voltmeter in parallel with a cranking circuit to indirectly measure the resistance on both the ground side and positive side. Don?t pull out the CC tool until you know the wiring, solenoids, etc is not the problem.
The Odyssey battery problems you?ve had are much different than what I?ve seen, I?ve had no problems at all with them, even recovered one that sat dead for a month.

Tim Andres
 
Agreement from me too however I did stress this to the original poster, via a phone call - with most electrical ‘issues’ you need to drill down to the basics first - it was a lesson I learned with an aircraft way back in 1997 :rolleyes:
 
So the NL starter apperears to cost the same and only weight 1 extra pound over the light weight one. Maybe this is a worthy modification during the engine ordering.
 
So the NL starter apperears to cost the same and only weight 1 extra pound over the light weight one. Maybe this is a worthy modification during the engine ordering.

My Thunderbolt engine is being built now. I emailed Jeff and asked him to switch - he was happy to do so. Not disagreeing in any way with the value/importance of doing all the appropriate troubleshooting, but I like the idea of "tried and true".
 
I have had he same experience. The NL starter cranks tons better than the xlt on the 540 and, I?m sure, on other models, especially with high compression.
 
One of the "secrets" to the NL starter is no secret at all... It has a significant mechanical advantage due to its massive gear reduction. I'm not sure any other starter bests the reduction of the
NL. Hard to beat good old fashioned leverage!
 
All Fixed

Thank you everyone for your helpful advice. I wish to report that I took out the permanent magnet starter motor and installed the 149-NL as recommended.
What a difference. I know Vans said it was a bit disappointing when people use their credit cards to fix things. However this was the correct fix. I now find it a bit disappointing that Vans did not warn us that they were delivering the IO390 with a cheaper starter motor that does not operate as efficiently as a 149-NL. Had I known that at time of ordering I would have saved myself some grief. My advice, do not accept the 149-12LS starter motor that comes with the stock standard motor from Vans, elect to have the 149-NL and you should not have any trouble with getting the motor through the first compression stroke.
One more final suggestion is to install an earth lead direct from the battery to the engine, this makes a lot of sense and it did appear to help the old starter motor get through the first compression while I waited for my new 149-NL starter motor. Don't know why Vans does not recommend this earth lead in their firewall forward instructions and kit.

Alan
 
FWIW

Thank you everyone for your helpful advice. I wish to report that I took out the permanent magnet starter motor and installed the 149-NL as recommended.
What a difference. I know Vans said it was a bit disappointing when people use their credit cards to fix things. However this was the correct fix. I now find it a bit disappointing that Vans did not warn us that they were delivering the IO390 with a cheaper starter motor that does not operate as efficiently as a 149-NL. Had I known that at time of ordering I would have saved myself some grief. My advice, do not accept the 149-12LS starter motor that comes with the stock standard motor from Vans, elect to have the 149-NL and you should not have any trouble with getting the motor through the first compression stroke.
One more final suggestion is to install an earth lead direct from the battery to the engine, this makes a lot of sense and it did appear to help the old starter motor get through the first compression while I waited for my new 149-NL starter motor. Don't know why Vans does not recommend this earth lead in their firewall forward instructions and kit.

Alan

It is great you got this solved. I have to say in your location and situation this was the best solution. I do think there might be an issue with that starter though, and to your comment about Vans, you might want to send a note to the engineering manager/VP, Rian. The little I heard from him at the banquet was impressive and he is about continuous improvement. He might just authorize post to send that starter back and see if it still meets the specs. I bet that it does not, and either way Vans can either recommend the NL or work with the supplier to ensure quality of parts is improved.

As an example, a little thing, but the 7 has a deficiency in being able to keep the rudder counter weight tight by the print build. People have used a connector with plate-nuts to allow tightening later in maintenance by eliminating the blind nut. That change has been adopted by Vans now and now comes with the 7 rudder kits. This is consistent with what I heard him say at the banquet.

Hope to hear he wants that starter back.
 
Glad you got it working also. I'm also very glad to hear that Rian may be more accepting of improvements to kits. This is a definite change from the past, if it's true. The NL starter is absolutely the better starter for the IO-390 and IO-540, and should be the standard starter. There are many things over the years that SHOULD have been improved in the kits, but never were, and it's a relief to hear that it may be changing.

Perfect Example: If you ever paid attention to the wheel fairing extension brackets on the main gear of the RV-10, people were having them break, and I had a machining company produce over 320 of them for early RV-10 builders to make them strong. That's 160 or more lucky RV-10 builders who never had to deal with them breaking. I talked to a person AT VANS once in the past 2 years or so who said that they broke MULTIPLES of these on their RV-10 demonstrators, and finally one of the staff said to just go buy some that were made exactly like the ones I had made up. (Plans are on my site). Does it really take the kit company breaking them a few times to wake them up? But, (and I'm not positive of this), I do not think the RV-10 is being shipped with anything different in the kit for those parts since 2005-2007 when builders actually were starting to have issues.
So if they are now open to things, this is a sea change indeed.
 
I talked to a person AT VANS once in the past 2 years or so who said that they broke MULTIPLES of these on their RV-10 demonstrators, and finally one of the staff said to just go buy some that were made exactly like the ones I had made up.

Tim,
Just because you talked to someone in person at Van's doesn't mean you got a proper understanding or the correct info.

None of Van's RV-10's have the alternate design part that can be made from plans on your web site. They still have the updated version (which is not what was being supplied in the kits initially) of the original design part. Is it the perfect solution? No, because there has been a couple breakages in the ~15 years that the airplanes have been flying (in rather harsh flight conditions compared to what a lot of owners RV-10's experience). There is a desire in engineering to redesign the part when there is engineering time to do so but just like anything else in life, priorities have to be made and it admittedly hasn't been a real high one.

You have always been very vocal about improvements that Van's should do, but relatively quiet when improvements are made (of which there are literally hundreds every year but they often go unnoticed). Van's is a small company with very finite resources.... I think we do a very good job of managing and prioritizing those resources though once again just like real life, you can't always please everyone.......... but we keep trying.
 
Thank you everyone for your helpful advice. I wish to report that I took out the permanent magnet starter motor and installed the 149-NL as recommended.
What a difference. I know Vans said it was a bit disappointing when people use their credit cards to fix things. However this was the correct fix.

I assume by "Van's said" you are referring to me?????

My comment was made as an effort to help you, not criticize you. As mentioned previously, the forums are full of posts from people that shotgun parts to solve a problem. It is even possible that you still have an issue with your starter electrical system that has been compensated for by installation of a better performing starter.

I am glad you are happy with the result of your change, but I suggest you keep a close eye on the starter motor. It is not entirely the holy grail that you might think it is (search the forums for some of the problems that people have experienced). It has had it's share of problems and even though the cranking performance is better, we have stopped using them on our company aircraft.
 
Scott, is there a formal "product improvement request" that might be filed to ensure that the right people at Vans would evaluate the ideas? Of course they would need to be fully documented and appropriately explained.

BTW - I just happened to get a TXT from a 7 builder with the improved standard parts for rudder counterweight inside fasteners within minutes of Rian talking about improvements being implemented. If I had not been working with this builder I would not have known about the improvement coming standard. It's hard to compliment changes if they are not known.
 
Seems like we are dancing around the bush here a bit without exactly spelling out the concern for people. The concern I am aware of from my own experience and what Ive read on VAF regarding the 149NL starter is that the small diameter bolts that hold the starter together sometimes loosen significantly. What appear to be oil-like stains on the starter are a tell-tale sign. Check the bolts!

Is there something else Im missing?

With the above exception, the 149NL has worked well for me and was a significant improvement over the original lightweight starter that came with my engine. Money well spent in my case.

erich
 
Yep. Those bolts are 10/32 and I replaced them with drilled head AN bolts and lockwired them. No issues since.
 
My IO390 is on order and when I inquired with Lycoming about substituting the NL starter I was told that since my engine is stock they would not make the change. Guess I go with the lightweight starter for now.
 
My Recent Upgrade

As a data point for this topic - my experience is similar to Alan's described in his original post.

I have never been happy with the starter on my O-360. My engine came with a light weight Kelly Aerospace. I have always used the typical Odesey 680. If the engine is warm and/or I had the oil pan heater plugged in it would be just okay but ALWAYS had trouble with the first compression stroke. I checked the master and starter solenoids this year and the total volt drop at the starter was well within specs of the troubleshooting guide listed on the first page of this thread.

So, this inspection I decided to try the sky tec 149 NL starter. Works great! Wish I had done this years ago, probably would have saved me at least one new battery.

Jim
 
None of Van's RV-10's have the alternate design part that can be made from plans on your web site. They still have the updated version (which is not what was being supplied in the kits initially) of the original design part.

Can you elaborate on what the updated design is?

Larry
 
Back
Top