Yanmar 1GM10 - White smoke, no start

[nickj]

Hi all,

I've been having real issues with my 1GM10. The problems started with a large puff of white smoke, and the engine stopping completely. She went un-attended for four months (I stopped sailing), and just recently I have had the chance to look at the engine.

After much head-scratching, I pulled the injector out, only to see it was completely clogged. I thought this was the issue, and promptly replaced it. I also installed a Racor fuel filter (I had been only using the single filter onboard the engine...), and also installed fresh fuel lines. I replaced the engine-mounted filter, bled through the system and found a bit of water in the tank, which, thankfully for the new Racor I can see - I drained it, and pumped through all fresh fuel. I bled out all the usual spots, and then cranked the engine at full throttle with the injector line unbolted - Fuel is coming through as it should.

The engine cranks, and copious amounts of white smoke comes out of the exhaust. The boat is on land, so I've been cranking it with the impeller out. You can hear the engine wanting to start, but it just can't do it. A considerable amount of white smoke is coming out, and it is definitely smoke, not water vapour/steam.

I've just spent four hours breathing this smoke in, re-bleeding the lines, bypassing the new Racor to make sure it's not that... Etc. Eventually I pulled the new injector out, and ran it pointing upwards so I could confirm there wasn't another blockage - The spray pattern is excellent, so the injector pump appears to be doing a good job, and the injector is definitely not the issue.

I simply don't know what else could be wrong... Maybe it is compression? Is it possible it's the head gasket? If so, should there be visible leaks or any way to see that is the problem without some kind of compression tester? I did get it started last week briefly, and the engine was very un-responsive to any throttle movement...

Prior to all this, the engine had over time begun to blow more and more white smoke. At one point I had overheating problems, however they magically went away. I could never figure it out... I even tried with an infrared thermometer and the engine was at a reasonable temperature... The seacock was never blocked. It was, and still remains a mystery. I only mention it as it may help in a diagnosis...

I head out across the Pacific this year, and I'm very nervous about never getting the engine back to a reliable state... And funds are running low as always!

Cheers, Nick

[rtbates]

I had the same problem with my older 1GM, 6.5hp version. Twas a blown head gasket. Check your exhaust elbow for corrosion caused holes, especially if your 1GM is seawater cooled (no radiator).

[nickj]

Originally Posted by rtbates

I had the same problem with my older 1GM, 6.5hp version. Twas a blown head gasket. Check your exhaust elbow for corrosion caused holes, especially if your 1GM is seawater cooled (no radiator).

Thanks, that's very helpful - The engine is raw water cooled.

So checking the exhaust elbow - Is that a separate problem to the possible head gasket, or is a corroded or holed exhaust elbow a diagnostic sign that it is or may be blown?

Is there any way to tell visually if it's a blown head gasket?

Thanks again, Nick

[Boracay]

You don't say how old the engine is, or how many hours it has done, but my guess is that it's an old engine with a lot of hours and it's feeling it's age.

If this is the case then your optimum action is to replace the engine, gearbox and associated systems.

Otherwise it may be best to pull the engine and have it reconditioned (esp. the bearings and oil pump).

[rtbates]

Originally Posted by nickj

Thanks, that's very helpful - The engine is raw water cooled.

So checking the exhaust elbow - Is that a separate problem to the possible head gasket, or is a corroded or holed exhaust elbow a diagnostic sign that it is or may be blown?

Is there any way to tell visually if it's a blown head gasket?

Thanks again, Nick

Could be the rote cause. What happens is the elbow inner jacket corrodes through and now sea water enters the exhaust port every time the motor is shut down. Over time this water sits in the exhaust area and can (and did in my case) corrode a hole through one of the push rod tubes and now the engines internals are open to the exhaust port. I've even heard of 1GMs sucking in so much water through this hole to hydro lock. Carry a spare exhaust elbow with you when you go into the Pacific. When replacing the head gasket follow Yanmar's instructions to the letter. Use a good gasket adhesive/sealant. I did not the FIRST time and had to replace the gasket a second time with sealant. Some folks say not to use any sealant. DO NOT LISTEN TO THEM!!!

good luck

[nickj]

@Boracay - Engine replacement is not really an option. I'll go without an engine if that's the case. It was new in the year 2000, on land for four years, weekend use for two years, and then I got it. No idea how many engine hours it has. I probably put 600 on it...

Thanks Randy, I'll go back to the boat in the morning, and take a good look at the exhaust elbow.

[DJR]

" When replacing the head gasket follow Yanmar's instructions to the letter. "

Hi all... First time user here....

I too have a Yanmar 1GM10 and am wondering if anyone can point me in the direction of an operators instruction book?
Maintenance manual?

[GordMay]

Take a look here for Yanmar manuals:
http://www.cruisersforum.com/forums/...uals-8758.html

[Tellie]

Prior to all this, the engine had over time begun to blow more and more white smoke. At one point I had overheating problems, however they magically went away. I could never figure it out


Ahhh the Mechanic fairy strikes again.
White smoke, overheated, very good chance you're leaking coolant. Head gasket or cracked head. When funds are low you become your own mechanic. Replacing the head gasket on a 1GM is not a hard job and it'll give you a much better look see as to what's going on inside the head.

[DJR]

Thanks Gord May.. maybe it's just me but no sign of any Yanmar 1GM 10 manuals on that link...

Really it's the manufacturers service manual I'd be interested in..

I'll keep trying....

[GordMay]

As listed at the previously-linked On-Line SHOP MANUALS post ...

Yanmar Manuals can be downloaded here:
motoren.ath.cx: Yanmar motoren, motors engine | manual download

"Motoren" Includes:
GM-HM Workshop manual (PDF 60Mb!!!)
1GM10-2GM20(f)-3GM30(f) (PDF file plm 0.5 Mb)
1GM10-2GMFL-3GMDL (PDF file 1.5 MB)

See also GM Series Owner’s Maintenance Manual:
http://www.bluemoment.com/manuals/Yanmar.gm-series.pdf

[gonesail]

i had a cracked exhaust manifold on my 2GM that caused white smoke over 2000 rpm .. so check that too.