sittingduck
New member
A couple of years ago I bought an older 14" boat with a 30 HP Yamaha 2-stroke on it (1998 model) and I've never been able to get it running right. I rebuilt and synced the carbs and set ignition timing according to specs. Also installed a new impeller. This morning I replaced the diaphragm in the fuel pump and went for a test ride immediately thereafter and had it running great for 15 minutes and thought I had cracked the puzzle. Which in turn made me comfortable about bringing the family out for a ride. Then after running great for another minute it did what it's always done: Engine loses power and when trying to apply throttle again, the engine starts shaking/knocking heavily when throttle is applied. If in neutral and using the fast idle theres's heavy knocking every half second or so with the engine visibly jumping to one side. I can run it fairly when just above idle (but still kinda rough like I'm very near to having it knock/vibrate), and as soon as more throttle is applied, the knocking/shaking starts again. And it's not like I can "push through it" with the throttle lever - it's as if the lever becomes hard to move because of the strong vibrations. It sounds reallly unhealthy so naturally I always ease back immediately.
What puzzles me the most is that I had it running great this morning, and now it's horrible again. I'm running premix until I'm sure the autolube is working, so it might be running on a pretty rich mixture but I can't see that being the reason.
I could really use advice on how to proceed. It's in the water at the moment, and I don't have a trailer for it to take it to a mechanic, and I'd rather not shell out about a thousand bucks for a trailer (trailers for this specific boat are costly), before I know it's salvageable.
Here's a short clip on Youtube of what the issue sounds/looks like: https://www.youtube.com/watch?v=MM4Jz2FDaF0
Thanks in advance.
What puzzles me the most is that I had it running great this morning, and now it's horrible again. I'm running premix until I'm sure the autolube is working, so it might be running on a pretty rich mixture but I can't see that being the reason.
I could really use advice on how to proceed. It's in the water at the moment, and I don't have a trailer for it to take it to a mechanic, and I'd rather not shell out about a thousand bucks for a trailer (trailers for this specific boat are costly), before I know it's salvageable.
Here's a short clip on Youtube of what the issue sounds/looks like: https://www.youtube.com/watch?v=MM4Jz2FDaF0
Thanks in advance.