planing problem

[bassman7225]

I have a 1996 Mariner 200 EFI on a 200c Skeeter
the prop is original with the boat, I have 115# of compression in all six cylinders, new plugs and have just added some sea foam fuel treatment, the engine builds rpm slowley untill about 3200 rpm and then planes off. Mt top end rpm is about 5800 rpm this power head has less than 150 hours on it and used to plane out much better with this prop.

any help with where to look next?

thanks

[HStream1]

When did this start happening? All at once or over a period of time?

[bassman7225]

i am not really sure i guess it was probably gradual. it started last year

[HStream1]

Skeeters are heeeeavy.

In that it was gradual beginning last year. While checking compression is a good start. But If I were you I'd do/have a leakdown done on the motor. If leakdown is 10% or lower, Great ,10% or better that may be some of if not all your issue. It's a 96 so the possibility of injectors needing a good service also comes to mind. Within the last year or two ethonol has created some similar problems not just with injectors but with fuel line deterioration. Take a look at possible water log also.

Just throwing some possibilities out at you not actually having one on one experience with your situation. I'm sure you'll get other suggestions that will be helpful.

Good Luck!!

[bassman7225]

thanks for the input.

just a few other facts


the power head was replaced with a factory powerhead about 5 years ago, not rebuilt and has less than 150 hours on it and probably less than a 100 hrs. do you know of an easy way to check out the injectors?

[HStream1]

Injectors need to be put on a flow bench to simulate actual operation. I remove mine and send them to Brucato. a set of 6 runs $140.00. They clean them in a solution and ultrasonic tank. then calibrate them.

Check your hoses for ethanol deterioration. Thats a good place to begin.

[jacklake2003]

Maybe check for water in the hull. Do you notice it sitting a little lower in the water at rest? You might have some water somewhere.