A moment of weird RPM issue...

[Nosnibor]

Hey all, long time no post.

If y'all remember this was my first season owning a boat. Everything seemed to be flawless. I went out the other day and during some mildly rough water/wind I was getting no response at certain RPM ranges. As I moved the level it seemed as if nothing was happening. Realizing this wasn't right I decided to turn the boat off and try to feel under the intake grate. The water was choppy and I couldn't stay under for long but I did manage to pull 1 or 2 strands of what I guess was sea weed. I couldn't feel anything else hanging from there so I don't know if anything else was up in there. I started the boat and eventually the water calmed down. I attempted throttling again and it seemed to run normal. From there I went on for about half an hour at full speed with no issues.

So could it have just been a moment of some sea weed clogging up in the intake or is there something more serious I need to check. I really have no idea of anything else unless if maybe a fuel line was getting clogged. The boat had been sitting for about 3 weeks since the last use. Thanks for any input.

Nos

 

[James.Moon]

By getting no response, do you mean the engine would rev but boat not move much? If you get anything through the grate into the jet pump, this will happen - it will cavitate i.e. rev but go only very slowly 5 MPH ish - try shaking it by coasting or reversing per the manual - do not run it very long when cavitating as the exhaust cooling will not work under these circumstances and it will eventually fry the exhaust cooling water intake and sink your boat! If you can't shake the obstruction after a few tries, call for a tow or a water taxi.
Weeds will often kick out, but if you pick up a stick or a dock rope , it will not come out.
I have had experience with both - probably the worst feature of a jet boat - never seem to pick anything up at speed, but idling near shore seems to increase the odds. I have been boating 6 seasons and have picked up weeds maybe 4-5 times and always able to clear them - however I picked up a stick in 2010 and a dock rope in 2015 - both had to be fished out on dry land.

 

[Nike12000]

Could be worse my brother wasn't watching when we were tubing...

 

[Nosnibor]

By getting no response, do you mean the engine would rev but boat not move much? If you get anything through the grate into the jet pump, this will happen - it will cavitate i.e. rev but go only very slowly 5 MPH ish - try shaking it by coasting or reversing per the manual - do not run it very long when cavitating as the exhaust cooling will not work under these circumstances and it will eventually fry the exhaust cooling water intake and sink your boat! If you can't shake the obstruction after a few tries, call for a tow or a water taxi.
Weeds will often kick out, but if you pick up a stick or a dock rope , it will not come out.
I have had experience with both - probably the worst feature of a jet boat - never seem to pick anything up at speed, but idling near shore seems to increase the odds. I have been boating 6 seasons and have picked up weeds maybe 4-5 times and always able to clear them - however I picked up a stick in 2010 and a dock rope in 2015 - both had to be fished out on dry land.

I think what was actually happening was I was pushing the throttle up and the RPM's didn't go up past 5k. I was in some rough water and after a little while I was able to go full speed again. Ran fine after that. Boat is winterized now. The techs said everything looked good and it got good compression numbers.

 

[Nosnibor]

Could be worse my brother wasn't watching when we were tubing... View attachment 33526

Wow, that sucks. I have a bad rope scare the first time I went out with my boat. Luckily it only got tangled in the gate and not the impeller.