4-108 Starter motor

[keelhauled]

I spent half my fishing time last year either in dry dock or in the motor dealers because of an on going problem with the starter on my Perkins 4-108. Some of the problem is down to the fact that the starter is so near the bilge. Im also afraid that the starters ive bought are not marine grade. Have any of you had similar probs??? Im so nervous now ive lost confidence in going out for fear she wont start.

 

[rich]

Do you mean that the bilge water is getting into the flywheel bellhousing?

 

[keelhauled]

Yes Rich i suppose some water/ condensation from the engine well would get into the internal workings.

 

[rich]

Then That, is the problem, try and keep water away,

 

[Peterduck]

I used to have starter motor problems with a BMC diesel which I had. An auto electrician explained to me that my problem was trying to start with batteries which were too low in charge, and plugging away at it trying to get the bloody motor to start! When voltage is down, the watts required by the motor remain the same, so the amperage used goes through the roof, burning out the motor. Nothing to do with water, either salt or fresh. I have never heard of a "marine grade" starter motor, although the Gardners may have such a thing.
Peter.

 

[aztec]

as far as marine grade goes...

one of my engines is fitted with a "marine" starter, the other with an identical van type. the marine one has rubber seals in the solonoid, and the casing is sealed...

or it was... both will play up if left for some time due to corrosion, the best bet is to stop water affecting them... how that is achieved i'm not sure about but after their yearly rebuild, i make sure that they're nicely greased, and then give them a good coat of engine paint... seems to work ok.

i'm not certain why the marine one is "sealed" there may be two reasons, one is to prevent damp, the other is to "spark proof" it. making it a little safer on petrol engined boats.... as in a simmilar case, some "marine altanators" are sealed for the latter reason...

or so i am led to believe.

 

[seo]

A true exposed duty starter may have had the windings sealed with an insulating spray that's called "Glyptol" here in the colonies.

The comment on low voltage is quite correct. The starter shouldn't be cranked for more than (about) the count of ten, and then given a cooling interval of the count of twenty. If the engine is kicking on one or two cylinders at the count of ten, keep cranking, because the voltage draw is very low; the engine is doing most of the work in that case.

For a boat with very shallow bilge, it might be worthwhile to fit something like an American Rule "computer" pump. This is about 75% marketing, consisting of a timer and a current sensor inside the submersible pump. The pump automatically cylces every couple of minutes. The pump runs until the current drops, indicating its sucking dry, then it quits. An irritating thing to share a sleeping cabin with, but very good at keeping the bilge sucked to the minimum.

The best marine conversions have the starters mounted on the top of the flywheel, with the starter protruding aftwards, over the reverse gear. Easy to get at, far above the bilge. Good thing. Perkins never made one that I'm aware of.

Perkins 4-108's that were marketed in the US were fitted with Delco starters, while 4-107's were fitted with Lucas (Prince of Darkness). The Delco is very durable and quite a bit cheaper. They aren't interchangeable.

My boat has an odd hybrid engine, 107 wet-sleeve block, 107 mechanical governor injection, 108 flywheel, bellhousing, starter, 107 fuel-igniter starting assist, 108 Bowman heat exchangers, 108 Hurth reverse gear. Best of all possible worlds. It's still a hopelessly obsolete iron, but parts are cheap and available worldwide.

seo