New 1GM10 RPM Problems Continued

[jddj]

The 1GM10 in my CD 25D was installed last spring and ran perfectly all summer - now ~50hr. Could easily get 3400 in forward. Spring maintenace was done by boat yard and consisted of changing both filters and the oil. My earlier post indicated I could now not get above 2400 rpm tied to the dock. Today we stepped the mast and she was free. However, still could only run at ~2300 rpm. Pushing the throttle any further forward did not increase rpm but the engine ran ragged - seems to be missing. I could briefly get to 3000 rpm in forward then the rpms dropped by themselves to 2400 after about 10 sec with rough running. Air filter clear, new primary Racor 2 micron (vacuum gauge reads 0) and new secondary filter on engine. Now what? Any recomendations for a really good Yanmar mechanic with reach of Guilford/New Haven CT?

[Tynaje]

I know this is a Perkins issue,but sounds familiar to yours...
http://www.canaljunction.com/boat/engin ... WONT%20REV

OOPS scroll down to Perkins wont rev

[Jim Davis]

I've had this happen with crud (sand, mud and carbon) build up in the mixing elbow water inlet. You can remove the water hose going to the elbow, then remove the brass hose barb. Look in the hole, if it is plugged use 12 gauge solid copper wire to clean it out. Then use a .410 shotgun bronze bore brush to clean the threads.

Just a thought.

I see you have also asked on my favorite place for answers on Yanmars.
http://www.freeboards.net/index.php?mfo ... ct=SC&c=20