Grady White 330 Express/Yamaha 250’s

[TComer]

My port engine shuts down to 2000 rpm after powering up following trolling or idling through no wake zones. It will not exceed 2000 rpm’s until shut down and restarted several times. I had the cam sensor replaced, but that did not solve the problem. I have heard that the anti-siphon valve, which is spring loaded, might be to blame. This is a 2005 boat and engines, with about 1480 hours. Until now, the engines have performed flawlessly. They have been well cared for and serviced. I appreciate any ideas about how to solve this problem.

 

[HMBJack]

I'd check the VST filter if it has not been cleaned or replaced in the last 700 hours.

 

[drbatts]

Sounds like the VST

 

[g0tagrip]

There are three cam sensors on those engines, did you replace all three? I had a similar problem with one of my F250s and we replaced all three since I could not determine which one was the culprit. However it did fix my problem.