Wondering if anyone has any idea on this.

I was out tonight and both engines were running strong at about 4700 rpm's. Came off plane to go under a bridge and then started to throttle up. As I neared full throttle the port engine dropped about 1000 rpms. (my buddy in back said it sounded like I was hitting a rev limiter but I don't have limiters.)

I came to a stop, killed the engines, and trimmed the drives up. Couldn't see anything wrong.

Started the engine again and didn't hear any problems. Came back up on plane and the engine started to rev strongly and then as I neared full throttle it dropped rpms again. Came back off plane looked again and saw nothing.

Throttled slowly up again and it came up and stayed at full throttle with no drop in r's.

Stopped again and throtled up fairly heavily and found no problems. R's stayed up and didn't hear anything. Ran it for a mile or so on the way in and everything seemed fine.

Any ideas anyone?

It could be moisture in the Distributor. Or a loose ground. Don't you hate those intermitent problems. They drive you crazy because you know you can't find them until they break. Just some thoughts.

Thanks Mitch,

Hadn't thought about a ground problem and I don't think it would be a moisture problem but it could be. Who knows.

My first thoughts are something with the fuel system so I am going to change the fuel filters and see what happens.

Kohldog,

It could be a fuel obstruction somewhere between the tank pick-up and the jet if it has carb. Don't hold the throttle down if it won't rev properly, you could do serious damage to the motor.