Starter motor maintenance -4108m

[John Tyler]

I have just had my starter motor reconditioned – rusted up – and wonder if anyone else has any info on how to avoid a rusty starter. I have a 4108m & 2 pin starter motor.

There seems to be a few points:

1. Do owners grease the join between the starter & engine block or use a gasket maybe?

2. The sump area below the engine & starter can get wet and the starter is low lying anyway, so prone to damp etc. I am considering drilling the sump rear wall by the starter to allow any excess water to drain back into the bilge below the drive shaft – easier to drain with sump drain pump than the actual contained sump area directly under the engine.

[Van]

Hi John,

Timely question – I was just today looking at my 4-108M starter motor and thinking “ugh, that’s rusty, I wonder if I should be worried”.  I think the rust is superficial, but must admit I have no confidence in that.

What should we do to protect it?

I’d be hesitant to drill the sump wall to allow liquids to drain into the bilge – that could include oils like diesel if you had a crack in a high pressure hose.  Your bilge pumps would end up pumping the diesel overboard.   We had just such a leak, and it was contained in the pan under the motor.

A related question – as we prepare to head off into remote areas of the S Pacific, should we be carrying a “spare” starter motor?

Van

 

[John Tyler]

Hi Van

Interesting what you say, as always. I did drill the hole but it is plugable to contain oil spills etc. I got my ‘newly serviced’ starter out again today as it was already rusted & the bendix would not slide along the shaft to engage the flywheel. I am now considering Kurust then thin Primocon paint to try & keep the gear rust-free. I wonder if an always-engaged starter would be possible on a 4108m, thus eliminating the need for the bendix to slide along the starter shaft.

Any ideas on this last point?

[Van]

Ah, this is beyond my domain of expertise!  For me, the 4-108 is the “beast” below the cockpit sole that I struggle to tame and keep happy…..

I like very much the idea of a plugable hole in the pan.  We just had our raw water pump start to leak (there is a special drain hole designed to leak water if the shaft seal fails, and that’s what happened).  Fortunately we spotted it after only a liter or so of water ended up in the sump.  But if it had been much more than that, I would have been happy to be able to pull a plug and drain it into the bilge for the pumps to deal with.

[John Tyler]

Hi Van

Good luck as you deal with/enjoy the Pacific. Re starters, I am going to get a spare. I think the chems used when the motors are cleaned often causes a deterioration in the ‘marinisation’ quality of the starter metal. The guy who cleaned mine will let me have one for £100/ $120 US, but I will buy new & hope the metal is more virile in anew one! At least they are relatively to get on/off and McLube is something to keep the metal marinised [of sorts]

Ciao

John

[PeterM]

Hi all,
I will add my starter motor story for what is worth…
We burned the starter motor out because the key switch did not spring back to the run position. The diesel started and ran fine, but the starter ran also, and the next time trying to start up, the solenoid clicked, but nothing else.
Our engine panel is now a pushbutton for the starter, so I think this is less likely, but a cautionary tale…
and of course we were in a really remote location for getting parts…
since then we have carried (the rebuilt) spare starter motor everywhere…

Peter M

[Rhapsode]

Here’s another story…

Our starter motor was playing up so we asked a starter motor man in Trinidad to take a look at it. He found the brushes were a little worn but nothing else.

I put it back on and we sailed up to Carriacou and then found it was still not working properly. The mechanic there diagnosed a solenoid problem. It being a sealed unit I thought I’d have to get a new one. Not so! The mechanic cut it open, cleaned it up and then welded the two halves back together again!

It’s behaved impeccably ever since. But a spare is on order!

[Murray Smith]

Just like Peter M, my key start switch did not disengage and I also burnt out my starter.  As this happened while I was being launched last week for the season, I had more on my mind and didn’t realize the starter was still engaged in time.  Besides the starter, I replaced the key start switch with a better spring action release.

 

[Van]

We had a similar problem but happily no burned out starter.

Our solenoid stuck in the “closed” position and the starter motor would not stop in spite of the ignition key position.

Luckily, we heard it, and jumped down below and killed the battery switch which stopped the starter.  Turned the switch on again, and the starter immediately started.  Well, it was like a new ignition switch, only big and red!

At that point, I took a large wrench and smacked the solenoid a few times.  (I can assure you, this was done, not in anger, but as a calm, controlled, well-thought out action).  This fixed it, and we have had no more problems.  On and off just as designed.

I am due to change the solenoid as soon as I get out from under the giant list of other things to do.

[Van]

Funny to be sitting here in Hawaii, with a state-mandated, COVID-19 lock-down due in 25 hours, and re-reading a bunch of old Nic 38 postings.

Rainshadow is currently in Hilo, but sans starter motor – we burned that out a couple of weeks ago, and the starter motor shop has one for me, which I plan to pick up, and install, in the 25 hours I have left!

I already tried installing it last week, but it didn’t work – the pinion gear did not engage the ring gear (flywheel).  But the shop tells me they know what the problem was, and tomorrow I am going to go in to try again.

I’ll probably have plenty of time to write up a description on our svrainshadow.com web site.  The new starter is a gear driven thing made by IMI.  Supposed to be immensely reliable.   We will see!

Van

[Van]

The shop was right, they fixed it and now it works.  The problem was that the new starter uses a smaller diameter pinion gear, and to deal with the smaller diameter, they have to shift the center of the starter motor towards the ring gear (flywheel) by about  1/8th, or maybe 3/16ths of an inch.  What this means, is that the thing is not rotationally symmetric.  And the spacer they had installed was 180 degrees out of place.  So, once they had rotated it, it installed easily and started the motor just fine.

FYI, it is an IMI-303, which is designed to fit Perkins 4-108 engines.

[Murray Smith]

Last summer my ignition switch also stuck and burnt out the starter. This Perkins 4108 is also used in Massey Ferguson tractors so I was able to get a new starter for $546. Can. from boyletractor.com and kept the old one which got rebuilt locally for an emergency spare.  I also changed the ignition switch to a push start switch.

[Van]

FWIW, the old Lucas starter was a direct drive unit, and the new one is geared, which means it uses less current (so they say).  It’s made by IMI and is their model 303.  The starter/alternator chap waxed lyrical about how incredibly reliable these starters are.  I hope he’s right, it cost almost $500.    To rebuild the old one was going to be about $250, and if we’d bought a new direct drive, it would have been about $375.

Because of the experience of having the solenoid stick (and reading of other people’s experiences with the ignition switch sticking), next to the key I added a bright little red LED light that lights up when ever the solenoid is engaged.  So, if the key sticks, or if the solenoid sticks, that little light will warn the crew that the starter motor is still running.

I also replaced the ignition switch with a much better one.

[Author]

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