Engine Vibration

[ronniepatel]

I own a 1996 Speedster 150 with 85hp twin Rotax. The problem is that whenever I accelerate there is vibration in the engines (both). At idle, and low speed there seems to be no problem. I have checked the carbs, propeller seals, propellers, jet oil....well most mechanical issues. Could there be some electrical issues or then....? Its been 2 weeks of trial and error and now I am totally confused. Any help would be appreciated

 

[seadoosnipe]

Balance Shaft

Ronnie, because I didn't do my normal research, I assumed that your engine was the 787cc Rotax. It has been brought to my attention by Dennis, that your boat uses the 717cc Rotax which is not equipped with the balance shaft. In it's need for harmonic balancing, the weights are part of the crankshaft at the connecting rods.
Sorry for any inconvenience this may have caused. Karl has mentioned the motor mounts, which I do agree could lead to vibration. What I find to be so weird is that your problem extends to both engines. If you find any other information that may be helpful in a solution to your problem, please forward it on to the forum!.......

 

[kustomkarl]

ronniepatel, welcome to the seadoo forum. I would look at the engine mounts. Grab the engine and give it a wiggle and tug it to see it you have any movement. Check both engines. It could also be that the impeller shafts aren't aligned properly if you just had a engine or jet pump rebuild. As centrifugal force increases ...as rpm's increase, it will get worse. The only real way to be sure of shaft alignment is to remove the pumps and check it. If you have had any engine removal or pump removal, this could be the problem. Give us repair history and we might be able to help you a little better, before you start pulling anything apart.

Karl

 

[seadoosnipe]

Impellors?

I know you said you've checked everything mechanical, but to me, it still seems that your problem could be in your impellors or shafts......propably from warpage or even picking something up that damaged your blades....