Loss of RPMs

[matt1978]

Hi, Guys

I hit a rock with my Yamaha 150 4 Stroke last week. We had the lower unit replaced. Now, when I throttle all the way forward it goes up to 5k RPMs and then slowly drops back to 4k (with the throttle still all the way forward).

If I throttle back and then forward again, it goes back up to 5k. But then slowly drops back down to 4k. This began to happen after I hit the rock and before I had the lower unit replaced (had to drive it home after the hit). I had hoped getting the new lower unit would solve the issue. The one we replaced was severely damaged. Big rock. Insurance covered it, thank God!

Any guesses regarding why I can't keep it at 5k RPMs? Why would it slowly drop to 4k and hold?

Thanks!

[rodbolt17]

sounds like the vst filters are stoped up.

[matt1978]

Yep. Thinking it's the filters. Will have them cleaned.

[matt1978]

Just realized the two issues (hitting the rock and the rpm loss) are unrelated. The filters just happened to clog about the same time I had the lower unit replaced.