Excessive smoking on startup Yanmar 2gm20f

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Terry Hackler

My 1990 Hunter 30 Yanmar 2GM20F diesel is very hard starting it seems. It takes 25-30 seconds and more sometimes before it even begins to start firing and then more time before it will stay running. Then once it does start it seems to smoke very excessively for another 15-20 seconds, totally enveloping the boat in a cloud of diesel smoke. It is mostly diesel smoke. A little of blue oil smoke also puffs at start up. Probably worn valve seals? Anybody have any similar experience with the 2gm20f in these regards? I estimate it has about 1200 hours on it.
 
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Bob E.

Yes

I have similar problems with a 1989 H30. It's worst in cold weather, better in warm weather. Engine runs fine once warmed up. I've been reading posts on this site for the 7 months I've owned the boat. Check the archives -- there are lots of owners with similar problems and lots of discussion. But also many people have no problems at all. My conclusion is that there are at least 100 things that could be wrong and cause these symptoms. Best guess is that the best way to fix it is to find a good Yanmar mechanic and pay big bucks. The "good" mechanic may be the second or third one you try. So far, I'm just living with mine. It seems to be getting better the more I use the boat, but that may be wishful thinking. I'll know more in the spring when the boat goes back in the water. Good luck with yours.
 
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Kevin

No

I have the 2GM20f in my 28,5 and it starts in about 2 to 3 seconds, with aliitle blue smoke puff about the size of a basketball. So why am I responding, the boat came with very good service records which upon review indicated this engine may have had a simular problem. In this case the mixing elbow was almost completely blocked and the owner compensated with full throttle at startups. Also they seemed to like to run the engine at idle and slow RPMs, definately a problem. Once repaired the records state all was well and I got the boat about a year later. I have had it for four years wiith no issues. I might suggest that if you are somewhat mechanical that you purchase a yanmar repair manual, there are quite a few things you can do prior to calling in the money guys. As far as the cold starting all diesels of this design ( no glow plugs or preheaters) start poorly/hard in 30 degree temps.
 
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Stephen Ostrander

Yes and no

How's this for ambiguity: I had a 2GM20 in my last boat (h28.5) and it started great, hot or cold. Now I have one in my new boat (h33.5) and it starts OK when hot but when cold acts just like yours, long cranking time and smoke puff. So go figure. I'm going to try cleaning the mixing elbow first, 'cause I can do that myself, but I'm leaving the injectors and valves to an expert, if it comes to that.
 
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Bob E.

More on "yes"

On mine, the injectors and filters were serviced professionaly just before I bought the boat. (I guess the previous owner was trying the fix the problem.) The first thing I did was inspect the mixing elbow. It had a thin coating of soot but had no obstruction. Since owning the boat, I've tried to operate the engine above 3000 RPM whenever motoring. One thing I think may be a clue is that it starts instantly with the throttle at idle setting if restarted within a couple of hours of being run. But after sitting a week, it takes full throttle to get it to fire, then several restarts to get it to keep running. Could this suggest a fuel problem?
 
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Paul

same with my 90 h30

My 90 h30 has the same problem. when cold, it needs full throttle to start and once it catches quickly bring it down to idle. when warm, it starts just fine with no throttle. Oh well, its been like this ever since I got it and I guess I'm just used to it!
 
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Sam Lust

Fuel

Terry; How old is your fuel and what color is it? It seems to me old fuel might be worth looking into. I've heard of old fuel causing smoking and I would think it would not make starting any easier. The fuel should look bright and clear.
 
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Terry Hackler

thanks for all the comments

The fuel quality should not be an issue as the boat is used extensively and we probably ran 3 or 4 tankfuls thru it this last summer. Tell me more about the mixing elbow, where and what is it? I am very mechanical but don't know much about diesels. I also heard that the valves could be adjusted to tight causing the hard starting. Any one ever hear of this?
 
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Don Riha

Instant starts

I once had your problem on my "90 Hunter 30. It was a leak in the "o" ring on one of the injectors. Once it was fixed the engine starts within 2-3 seconds, at 3/4 throttle, even when stored over the winter.
 
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Sam Lust

Manual

Get to Amazon.com and buy the Seloc Chilton Yanmar repair manual. It will answer all your concerns. It's realy good.
 
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