200 EFI struggles to get on plane

[spamn]

I have a 98 Merc 200 EFI and it has always ran great. One time I used it and it was just fine. The next time I used it I had this problem..

Starts and idles fine. When you go to get on plane it takes a very very long time. Eventually it will get on plane and run just fine. If you take it off plane just slightly, it will go back on plane. If you take it all the way off plane, the same problems occurs. Doesn't seem to matter how warmed it is.

Not sure if it's related but while investigating I noticed that there was oil all over the engine. The culprit was a cracked cap on the reservoir which is directly over the intake. I assumed the oil was running into the intake. The cap was replaced and intake cleaned up. Plugs were extremely fouled so they were cleaned... Didn't help the problem one bit.

Did a compression test. All cylinders were between 120 and 112.

Plugs are fouled every time you turn the engine on.

Haven't looked at the problem since last fall and it's that time of year so I'm ready to investigate again.

Any ideas on what to look at?

Thanks in advance.

 

[CharlieB]

Re: 200 EFI struggles to get on plane

Possibly dirty injectors, squirting, not spraying correctly. Poor atomization of fuel makes for weak low RPM, this also affects high RPM but not near as noticeable as making it harder to get on plane. Also tends to load up spark plugs, incomplete combustion, drops, liquid fuel does NOT burn.

I'd try adding high dose level of Sea Form to a small portable tank of fuel, 2 or 3 gal, and see if that makes a difference.

Then consider removing the injectors and send them in to Tony Brucado for proper cleaning, Tony also checks flow rates to be sure all injectors are well fit for service.