compression question...HELP

[air.boss1]

what should the compression be on a 1996 speedster? all cylinders are reading 110-120. The boat is running fine till all of a sudden I had no power in the port engine, It will start but does not idle and will not rev past 2800. out of the water it is ok, any suggestions? I have spark to all the plugs.

 

[Sportster-2001-951C-Stock]

Out of water isn't much of a running test, could be engine is firing on just one cylinder. Possible fuel system problem, in the case of two carbs per engine the cylinder that's not firing may have a gummed up carburetor.

Compression testing technique and compression gauge calibration can have a effect on results, a weak cranking battery can as well.

 

[Dr Honda]

Realistically.... a good Rotax... 800 or smaller... should be right around the 150 psi mark. If you gauge is good, and the battery is strong... then 110~120 is low.

 

[air.boss1]

thanks Tony, I started on the carbs and found the linkage between the 2 carbs broken. That would be my problem, I will check the compression after I fix the linkage. It runs really good so it might have been the gauge.