4 replies to this topic

[jamepc]

I have a 2001 Islandia, 240 Merc EFI. The RPM's won't go above 4900-5000 RPM's. I did a compression check and all were around 130 psi. Next, I would like to verify all cylinders are firing. What's the easiest way to do this? If 1 or more aren't running, how do I tell which ones? Any other ideas or suggestions regarding this problem are appreciated.
Also at idle to about 1500 RPM's the engine is extremely rough. Very shaky like a cam with a lot of overlap in a car. So if all the cylinders are firing, maybe something else is off balance like a bad impeller? Would this also slow the engine and boat down?
Thanks,
James

[jamepc]

Any ideas?

Thanks.

[gofast]

The easiest thing to do would be to pull all plugs ,keep them in order . compare to each other , you will be looking for one(s) wet with fuel. If one or more are not firing they will give u rough idle / poor performance. Yes,a worn wear ring or damaged impeller will cause cavitation and poor performance.

[jamepc]

The easiest thing to do would be to pull all plugs ,keep them in order . compare to each other , you will be looking for one(s) wet with fuel. If one or more are not firing they will give u rough idle / poor performance. Yes,a worn wear ring or damaged impeller will cause cavitation and poor performance.

Also, how should spark plugs look in this 2 stroke. They always have a black film of oil on them but that normal, correct? I don't smell raw fuel.

[gofast]

no they should not be black . here is article on 2 stroke plugs . its on bikes but the priciples the same. http://ezinearticles...ngine&id=170641