Yanmar 1GM

[SteveTibbetts]

I was looking at a boat yesterday with what appears to be a siezed Yanmar 1GM, an old one with the starting handle attachment on a spindle at the top. Having freed off the handle mechanism and removed both water pump and alternator belts i could not turn the engine at all. I also connected a known good battery and the starter just clicked. The engine will not have run for 10 years or so and i doubt its been turned over for at least a year. Do the good folks on this forum think the engine could be salvageable? Could it be the starter being engaged on the flywheel causing no movement at the crank? I read somewhere that early Yanmars with a horizontal cylinder 'suffer from water in the upper cylinder'.
I can competently follow a workshop manual and have rebuilt many engines in my time but cannot afford to buy a boat that needs a new engine!

 

[MASH]

Of course it is salvageable, presumably the real question is whether it is economically salvageabe and for that you need to strip it down completely and then make an assessment. Then spend some tens of hours determining the obscene prices of Yanmar spares (Just look at a gasket set for starters). And quit.

Having been there myself recently I'd say simply to relpace it with a new unit and then look to rebuilding or parting out the old one at leisure. This is far easier, less stressful and though may dent temporary cashflow probably won't cost more in the long run.

A time/salt/corrosion seized engine is severley damaged no matter how you look at it. Imagining it's just a WD40 job on the big ends is a dream. Like dreams it may, just may prove true. But on the other hand it almost certainly will not. Feel lucky, punk? Well, do you?

Keep it simple is the lesson I should have learned a year ago.

 

[Appledore]

Could also be an ingress of cooling water from the exhaust elbow. These corrode and allow any water in them to run back into the exhaust valve and cylinder head. Again, as Mash says, very expensive.

I obtained a YM 1 gm 10 for my boat, and found several little problems with it, so am slowly buying bits and bobs just in case. I checked what appeared to be a good looking exhaust elbow, only to find it was corroding inside! Now replaced that. Even with two batteries, my starter motor doesn't turn the flywheel, and I usually have to use the decompressor lever to get it swinging. Something else to buy!!

Might be better to buy a decent running second hand one, and keep your original for a stock of spares. I did buy a brand new Yanmar injector (£120-ish) from a seller on eBay for £48, and a spare water pump for £59. So the spare parts do add up considerably.

Best of luck with the project.

Geoff

 

[Tranona]

I was looking at a boat yesterday with what appears to be a siezed Yanmar 1GM, an old one with the starting handle attachment on a spindle at the top. Having freed off the handle mechanism and removed both water pump and alternator belts i could not turn the engine at all. I also connected a known good battery and the starter just clicked. The engine will not have run for 10 years or so and i doubt its been turned over for at least a year. Do the good folks on this forum think the engine could be salvageable? Could it be the starter being engaged on the flywheel causing no movement at the crank? I read somewhere that early Yanmars with a horizontal cylinder 'suffer from water in the upper cylinder'.
I can competently follow a workshop manual and have rebuilt many engines in my time but cannot afford to buy a boat that needs a new engine!

From your description don't think you have a 1GM, but a YSE8. Completely different engine.

Might be good as a seized 1GM is often not repairable, but a YSE8 probably is. However it is really old now and spares are getting hard and expensive. You can still get reconditioned ones from Cellar Marine in Cornwall which will be cheaper than a completely new engine as there is nothing that is a direct replacement so you will need to replace the whole drive train.

 

[William_H]

Diesel engine

And one last consideration. A single cylinder diesel is a very noisy engine and a twin is vastly better (smoother) if you are going to do any distance under motor. Consider reengine with a twin or even better a 3 cylinder. good luck olewill

 

[rotrax]

I was looking at a boat yesterday with what appears to be a siezed Yanmar 1GM, an old one with the starting handle attachment on a spindle at the top. Having freed off the handle mechanism and removed both water pump and alternator belts i could not turn the engine at all. I also connected a known good battery and the starter just clicked. The engine will not have run for 10 years or so and i doubt its been turned over for at least a year. Do the good folks on this forum think the engine could be salvageable? Could it be the starter being engaged on the flywheel causing no movement at the crank? I read somewhere that early Yanmars with a horizontal cylinder 'suffer from water in the upper cylinder'.
I can competently follow a workshop manual and have rebuilt many engines in my time but cannot afford to buy a boat that needs a new engine!

Before you give in, remove the injector and put light oil down into the cylinder. Leave a while-24 hours-and then try to rotate the engine by the crankshaft nut at the bottom pulley. If you can get it to turn you may have a chance ,If it wont, the previous posters advice is bang on.

 

[Stemar]

.../...
Even with two batteries, my starter motor doesn't turn the flywheel, and I usually have to use the decompressor lever to get it swinging. Something else to buy!!
.../...

Geoff

Before you inflict severe wallet pain on yourself, try taking the starter to your friendly local autoelectrician. He may be able to recondition it for a lot less than the cost of new.

to the OP - A new engine in a boat you're buying is affordable if the seller will (or has) reduced the price accordingly. Certainly better, IMHO, than one that's been brought back from the dead with a bit of WD40. To my mind, a Lazarus engine's always going to be a bit of a worry.

 

[NickRobinson]

Before you give in, remove the injector and put light oil down into the cylinder. Leave a while-24 hours-and then try to rotate the engine by the crankshaft nut at the bottom pulley. If you can get it to turn you may have a chance ,If it wont, the previous posters advice is bang on.

Better than main force, try turning the crank first one then the other way.

Or a blunt screwdriver on the starter ring gear (more leverage)

If the piston is stuck, you'll feel a tiny movement straight away. work it to and fro, with diesel down the injector hole (harder on a horizontal) and it should increase until you can get a whole rev. To and fro helps allow the gunge to move out of the way rather than snapping rings etc.

If NO tiny movement (which equates to normal play in the big end), that means the crank is seized and engine probably died running and is scrap or v expensive.

More likely to be the piston stuck out of use-

Nick

 

[SteveTibbetts]

Many thanks to all that have responded and given me some food for thought. I'll let you know how it goes!


Steve