Yanmar 10

[littlepati]

Hi folks advice on yanmar 10 1985 installation. Looking to buy a boat with a well maintained example. Obviously the engine is nocking on a bit. I will be able to see it running and should be able to take her for a spin. Will check the usual is there anything I should be looking for in particular . Cheers

 

[Topcat47]

Depends on the boat and the version of the engine. More info needed.

 

[DanTribe]

Hi folks advice on yanmar 10 1985 installation. Looking to buy a boat with a well maintained example. Obviously the engine is nocking on a bit. I will be able to see it running and should be able to take her for a spin. Will check the usual is there anything I should be looking for in particular . Cheers

Checking for regular oil changes is a good start.
Try to put it under a bit of stress and check exhaust smoke. White could indicate water in the system, could be bad.
Check if the exhaust elbow has been replaced. This is a common problem. A bit expensive to replace. Very expensive if neglected.

 

[andsarkit]

It should start almost instantly with little or no black smoke from the exhaust.
Usual problems are water pump seals failing which give drips from under the pump. This can lead to rusting of the oil pipes with resulting serious oil loss.
Engine mountings can rust badly and the rubber can separate.
Exhaust manifold can corrode internally causing water to enter the cylinders. This can only be inspected by removal of the 3 mounting bolts.
basically a strong but noisy engine but spares are way overpriced.

 

[Tranona]

Couple of other points to those already covered. The engine is seawater cooled and the pipes/hoses should be dismantled and cleaned from time to time, particularly the one running from the pump to the thermostat which has a pipe into the cylinder water jacket. There is an anode into the water jacket cunningly hidden just above the starter motor and consequently often gets ignored . Because it does not have glow plugs it needs a good kick from the starter to get going, especially when cold so battery and all connections should be sound. The wiring loom has a hidden fuse in the connectors and the connectors should be checked for corrosion.

Having said all that it is a super little engine and if looked after very reliable.

 

[littlepati]

Thanks guys will try and cover those points and ask for the documents the rest of the boat looks in nice condition. Cheers

 

[robbieg]

Agree about no black smoke when starting from warm. Starting from cold (particularly in colder weather) you may get some black smoke which could be considered normal. Don't know the engine but certainly the Yanmar GM version needs 3/4 throttle to get started from cold in colder weather and you will get black smoke (unburnt diesel) for a second or two. However, it really is only on first from cold in colder conditions. Once the engine is warm and in mid season it should start easily on less throttle (and so less black smoke). I think the starting proceedure in the GM manual covers this. Obviously if white smoke or blue smoke you need to investigate further.

 

[Topcat47]

Take very good care of the alternator. Replacements are EXPENSIVE and Chinese equivalents often aren't. The 1GM10 can't drive a bigger one on start-up and thick-over audit's the most powerful of the variants about. I fitted a chinese "copy" but it was a lot more powerful than the OEM Hitachi and we just couldn't get the engine to run it. As soon as the revs built enough to energise the alternator, the power drain stalled it. Pete from Marine Power diagnosed the problem in about 30 seconds. Proved that it was the alternator by disconnecting it and starting the engine. In the end the supplier of the alternator took it back and then re-wound and re-bearinged the original. It's still working. He had tested a sample of the supposedly equivalent alternators finding them all producing about 50% more than the Hitachi. It's only a problem for the 1 GM engines.

 

[penfold]

What's the difference in price? May be worth trying a larger pulley on the cheapo alternator to see if it offsets the higher load.

 

[LiftyK]

I had the same problem. The pulley size of the Yanmar alternator was different to that on the pattern (3rd party alternative) alternator. The engine would not start. I took the failed Yanmar alternator to a local alternator repair shop who brought it back to life for a modest fee. Problem solved.

 

[Topcat47]

What's the difference in price? May be worth trying a larger pulley on the cheapo alternator to see if it offsets the higher load.

The cheapo copy was about 1/3 the price of the OEM. I don't think a larger pulley would be the answer as it wouldn't kick in until the revs went proportionally higher. The load would still be significant then for such a small engine and it may not swing the prop well so you'd lose performance through the water (although performance in the case of the 1GM10 is overeating the pudding ).

 

[LiftyK]

The cheapo copy was about 1/3 the price of the OEM. I don't think a larger pulley would be the answer as it wouldn't kick in until the revs went proportionally higher. The load would still be significant then for such a small engine and it may not swing the prop well so you'd lose performance through the water (although performance in the case of the 1GM10 is overeating the pudding ).

My experience was:
- 1GM10 and copy alternator: engine would not start at all. A few chugs then all stop,
- 1GM10 with repaired Yanmar alternator: instant start.
I'm pretty sure the pulley does make a significant difference to the starting load and is a step too far, perhaps when combined with the potentially extra output of the alternator.

 

[B58]

My experience was:
- 1GM10 and copy alternator: engine would not start at all. A few chugs then all stop,
- 1GM10 with repaired Yanmar alternator: instant start.
I'm pretty sure the pulley does make a significant difference to the starting load and is a step too far, perhaps when combined with the potentially extra output of the alternator.

It depends on the alternator size and how much the battery drawing, That's why 1GMs's had a 35amp alternator.

 

[Topcat47]

I had changed the pulley supplied with the Chinese example for the original and it still stalled the engine.