Yanmar Starter Problems

[Terra Nova]

Originally Posted by Dockhead

...Yanmar starter problems...first happened to me five years ago, when my engine just wouldn't start...Since then, the Yanmar wouldn't turn over from time to time, but would, the next time I tried it, so I didn't worry about it.

...my sheet leads are not yet fully installed, and we didn't even bother to sheet inside the shrouds...

we pull off the starter, expecting to put on the spare I have -- and the spare doesn't fit...

Thanks for posting this. Just to show what can happen to even experienced sailors. And to showcase the importance of making needed repairs before leaving port.

Looks like the ring gear needs to be replaced.

[Pete7]

Dockhead, I think you are dealing with more than one problem and moving the engine with a breaker bar to make it start suggests a broken wire as Sailor Chick suggests.

Also is the pinion supposed to be greased? It's a long time since I played around with starters and replacing bushes etc, but I was always lead to believe that the pinion (or bendix if its that type) needed to be left clean and dry so that it slides easily and doesn't pick up dirt which stops the pinion sliding.

Pete

[arsenelupiga]

Originally Posted by Dockhead

And voila, the engine starts, and I figure it's solved. We sail on, the wind keeps rising, and I have my new carbon fiber blade jib, and we are smoking across the sea lanes. I go to bed for a couple of hours, and when I come up, my crew say that they've had two hours at an average of 11.5 knots, on a beam reach in 20 to 25 knots,

impressive speed for mono. Carbon fiber sails - you mean laminate ?

[Dockhead]

Originally Posted by jimbunyard

Yes, and from the description above it sounds like the problem may be something like what is shown in the picture below. Just under the center plug you'll notice that four of the teeth on the starter ring gear have been chipped off and if the engine doesn't start before it hits that section, or if the engine stops where that section aligns with the starter drive (which happens more often than would be presumed), the engine won't start.

If this is the case, nothing you do to the starter will help, but usually the ring gear is replaceable. You have to remover the gear, cover plate and flywheel, then break the old gear off with a hammer and a cold chisel, heat the new ring gear with a rosebud and oxacetylene torch to just before dull cherry red and drop the ring gear on the flywheel, where it shrink-fit locks onto the flywheel. It's a bit involved but not difficult. Last time I did it, on a Ford, the ring gear was 19.00.

You may be able to see if the ring gear teeth are messed up by looking through the hole where the starter goes or you may not.

Well, ring gear would be bad, of course. That would be pretty involved. Boat on the hard and blocked off, pull the shaft, pull back the gearbox, bleh.

We had the starter off three times, and every view of the ring gear we got looked fine. It must be harder than the pinion.

I think I would try replacing the pinion first and see if that does it, before doing the ring gear. I would even try deburring the pinion, except that don't the teeth need to have a certain level of smoothness?

Can the pinions be pulled off and replaced?

[Dockhead]

Originally Posted by arsenelupiga

impressive speed for mono. Carbon fiber sails - you mean laminate ?

Yes, they are laminate, with the matrix made out of carbon fiber and vectran, with taffeta on both sides. The difference is just incredible. We got to Guernsey in under 12 hours -- 110 miles. That's the fastest Channel crossing I've ever done by far, and that's despite fighting a foul tide in the Needles Channel, and then fighting 4.6 knots of foul tide in the Little Russel. But it was not just the speed, but the lack of heel -- in 25 knots of wind on a beam reach, only 20 degrees or less of heel. Furthermore, my old main was doing much more pulling than it usually does, without any speed bubble -- the air flowing smoothly from jib to main for the first time. I have done fast crossings with my old sails, but huge drag went with all the power, meaning lots of heel and a feeling of lots of force and power which is hard to control. With the new sail, it's like flying lightly with less heel, less sheet loads, far less stress in general. Maybe the sea state played a role, though; it was rather smooth for that much wind.

[Terra Nova]

If your ring gear is OK, then you might simply be having a very common Yanmar problem caused by running starter engagement power through the ignition switch. This only requires rewiring that power through a solenoid, so the starter gets full power. The symptoms of this are that the starter will just click when you hit start, not engaging the starter; often it will "click, click, click, and then finally catch.

[Dockhead]

Originally Posted by noelex 77

One possibility to consider from the symptoms is hydrolock. It results in intermittent starting with no electrical problem, as you have described. It can damage the starter ring gear or pinion teeth.

The diagnostic test is to see if you can turn over the engine by hand. However, in some cases the slow hand compression ejects the water and helps the engine starts normally. Just as you have described.

Hydrolock happens from incorrect installation (a very unlikely cause in an installation that has been unchanged for many years), a defective anti-syphon valve or an internally leaking exhaust elbow.

Yanmar have had some problems with hard to detect internal cracks in their exhaust elbow. They have redesigned the elbow to fix the problem.

The new part number is:
129670-13561
if you have the older elbow you need to be particuarly suspicious that this is the cause, although any exhaust elbow can leak.

This seems extremely unlikely, but it's intriguing. I have just replaced my exhaust elbow. It is a custom piece, and was done by a master. I don't, however, understand what leak you could be talking about -- leaking where? The elbow is quite a bit lower than the turbo, with a loop above -- hard to imagine how water could back up there. I have a water separator with below waterline discharge.

[noelex 77]

Originally Posted by Dockhead

The elbow is quite a bit lower than the turbo, with a loop above -- hard to imagine how water could back up there.

Where is the water injected?

The exhaust gases are very hot. Exhaust elbows have a double wall design with an inside tube that provides a jacket of cooling seawater. This internal tube normally extends above the cylinder. It is possible for this inside tube to corrode, or crack, allowing seawater to enter the engine. Water is incompressible so the starter motor cannot turn the engine over.

Some high rise exhaust elbows don't have an inside tube that extends above the cylinder head. Usually with this sort of design it is necessary to cover part of the elbow with some heat proof material such as a thick layer of fibreglass tape.

If your elbow has been custom made it is difficult to know what the internal design might be. The inside tube does not usually extend very far above the water injection point so if this is well below the cylinder head gravity will prevent water entering the cylinder head. With a conventional exhaust elbow an internal defect can cause the problem.

[DeepFrz]

DH, I think if you had hydrolock you would not be able to turn it over with the breaker bar. But if the ring gear is good then either pinion or wiring. Shorting across the solenoid with a screwdriver will give you a clue if its wiring or not. Of course we are just guessing from great distances.

[a64pilot]

I believe the gears on the starter are case hardened, filing will get through this hardening and the fix won't last long at all, yes the pinion can be replaced.
I'd have current starter re-built, and kept as a spare, I'd buy a new starter and as suggested use the ignition switch to trigger a solenoid, that triggers the starter solenoid.
I have the click, click, start issue myself, and need to do that, it is pretty common

[Stu Jackson]

Originally Posted by a64pilot

I believe the gears on the starter are case hardened, filing will get through this hardening and the fix won't last long at all, yes the pinion can be replaced.
I'd have current starter re-built, and kept as a spare, I'd buy a new starter and as suggested use the ignition switch to trigger a solenoid, that triggers the starter solenoid.
I have the click, click, start issue myself, and need to do that, it is pretty common

Dockhead, this is a very good summary. sailorchic's is, too. Whenever we have these issues reported on our engines (Universals) the cause is almost always an electrical one, so I would recommend checking that wiring. Almost all boat harnesses' weak points are the connections, then the wire size. Good luck.

[noelex 77]

Originally Posted by DeepFrz

DH, I think if you had hydrolock you would not be able to turn it over with the breaker bar.

That is what the textbooks say. If the cylinders are full of water from say a defective anti syphon valve that is obviously going to be the case.

With a defective exhaust elbow only a small quantity of water will get into the lowest cylinder. The water is kept out by the exhaust pressure so it can only enter when the engine is stopped. With a small pinhole leak you have the situation where only a very small amount of water will occasionally enter. It is only the lowest cylinder that is effected. If the exhaust valve is open when the engine is stopped the water will ejected and the start normally (or almost normally)

This produces a very intermittent problem.

I had this with an older engine and every time I tried the engine could be turned by hand. Perhaps just because of the valve position or perhaps because the slow hand compression allowed the very small quantity of water to pass the the valves and rings (the engine concerned had 6000 hours).

My symptoms were identical to Dockhead's.

I replaced the entire electrical starting system and had the starter motor rebuilt before the only remaining diagnosis was hydrolock. In my case it was complicated by a number of relays and solenoids in the starter system. With the high currents demanded by the locked motor these failed, further pointing to incorrect diagnosis of an electrical problem.

These sort of problems are most commonly electrical. The medical adage of "when you hear hooves look for horses, not zebras" has merit. In this case I would first look for an electrical problem, but it is worth considering other possibilities. Intermittent problems are very frustrating to track down and keeping your mind open is important.

[DeepFrz]

Intermittent problems are very frustrating to track down and keeping your mind open is important.

I understand this very well as diagnosing difficult problems was my livelihood. I was just trying to keep DH focused on the most likely cause of the problem and one way of trying to determine if that is indeed the case. The problem could be electrical, mechanical and as a long shot it could possibly but unlikely be hydrolock. That is just my opinion trying to diagnose a problem from 1000s of km away without much in the way of communications.

[hellosailor]

I would suggest sending out an oil sample for analysis. If there has been recurrent hydrolocking, that should have created excess water in the oil, and even if you can't see it in hand, the analysis would confirm or eliminate that question, I'd expect.
Cheaper and simpler than tearing apart the exhaust and engine, looking for tiny zebras.

[Dockhead]

Originally Posted by noelex 77

That is what the textbooks say. If the cylinders are full of water from say a defective anti syphon valve that is obviously going to be the case.

With a defective exhaust elbow only a small quantity of water will get into the lowest cylinder. The water is kept out by the exhaust pressure so it can only enter when the engine is stopped. With a small pinhole leak you have the situation where only a very small amount of water will occasionally enter. It is only the lowest cylinder that is effected. If the exhaust valve is open when the engine is stopped the water will ejected and the start normally (or almost normally)

This produces a very intermittent problem.

I had this with an older engine and every time I tried the engine could be turned by hand. Perhaps just because of the valve position or perhaps because the slow hand compression allowed the very small quantity of water to pass the the valves and rings (the engine concerned had 6000 hours).

My symptoms were identical to Dockhead's.

I replaced the entire electrical starting system and had the starter motor rebuilt before the only remaining diagnosis was hydrolock. In my case it was complicated by a number of relays and solenoids in the starter system. With the high currents demanded by the locked motor these failed, further pointing to incorrect diagnosis of an electrical problem.

These sort of problems are most commonly electrical. The medical adage of "when you hear hooves look for horses, not zebras" has merit. In this case I would first look for an electrical problem, but it is worth considering other possibilities. Intermittent problems are very frustrating to track down and keeping your mind open is important.

OK, thanks. How does a bad exhaust elbow lead to water in the cylinders? I can't quite imagine how this works. From a bad installation, I understand.