Limited rpm on Yanmar 2GM20F

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G

Grady

Have a problem with the Yanmar engine in our just purchased Hunter 30 that we believed was a binding cable between the cockpit and engine. The problem was there when we bought the boat but we (and the surveyer) didn't think it was a major issue. Wrong. The engine starts and runs fine up to 2500 rpms (in and out of gear)but a heavy and constant pressure must be kept on the cockpit control to reach even that rpm. Removing the cable at the engine showed that the cable moves freely and has normal travel. The resistance/binding is internal the the engine and is felt as soon as the engine speed control is pulled (at the engine). The resistance increases the further back the speed control is pulled and completly stops the speed control at about half its normal travel. The engine "no load speed limiter" and "fuel injection limiter" appear to have never been adjusted. Local Yanmar mechanics are few and far between. I do have a factory repair manual but do not want to do anything without some other input. Any body with any suggestions?
 
Dec 2, 2003
4,245
- - Seabeck WA
Suggest running it past yanmarhelp.com.

Sounds like you've lost a grommet or have a binding flinky,,,,,
 
Apr 24, 2006
194
Hunter 33_77-83 Mandeville LA
I have similar problem

My 2GM behaves the same way. I have been apprehensive about doing any thing because 1800 seems to be a 'happy' cruising rpm and it runs so well.
 
Jan 2, 2005
779
Hunter 35.5 Legend Lake Travis-Austin,TX
Chuck...

at 1800rpm, that Yanmar will "coke" up so fast you won't believe it. That may be part of the problem with Grady's, although it does sound like something else going on. Your Yanmar should be able to rev up to stated limits...3400 or so... and cruise at 2600-2800, anything less will clog it up big time.
 

kostas

.
Jan 27, 2006
14
- - Boston
I have the exact same problem

My 2GM20F is having the same problem. I am planning to have it checked during the off season. Boat mechanics are not easy to find nowdays...
 
G

Grady

Thanks for the input.

I have e-mailed Yanmar to see if they are able/willing to help. I will try yanmarhelp.com later today. I am convinced, at this point, that my trouble is in the engine governor system but who knows. I will post any useful information I find.
 
C

Clark

Grady, I've given your problem some thought . .

the last few days. Do you think that Scott Messer works on diesels? He is very good w/ outboards and working around the marinas here for quite some time, he may have developed some expertise with small diesels. I have his number if you want to check. Also, you may want to repost this to Ask All Sailors and in the Catalina forum too. Clark
 
P

Paul

Try a new exhaust elbow?

I had the same problem. Could not get any more than 2900 RPM. It went away when I replaced the mixing elbow (which was plugged pretty solidly). I now have a top speed of at least 3400RPM. The throttle has a heavy spring behind it that isn't easy to overcome. Any small kink or abrupt bend in the throttle cable makes it tough to operate, especially through the spot where the kink in the center cable passes by the corresponding kink in the outer jacket. It is easier to try to straighten this out than it is to replace the throttle cable.
 
G

Grady

Paul, the exhaust elbow is one of the

thing I need to look at but the problem I'm having now is at the engine speed control. My engine's resistance at the speed control lever is many times more than other Yanmar 2GM20 engines at the marina. When you changed the exhaust elbow did you also change the rubber hoses? And if so, did you find replacements from other than Yanmar? Hey Clark. Yes send me the phone number and I'll give him a call. Thanks.
 
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