Mercruiser 351 1976 - 233

[Sea Ray 220]

I got a Sea Ray 220 1976 with a mercruiser 351 with a rochester 2 barrel carb. It seems to run good at idle and mid range but when I go to full throttle it acts like it is starved for gas. Keeps hesitating at high speeds. So far I rebuilt the carb, new plugs, and fuel filter. The previous owner updated it to electronic ignition.

Any advice would be great, thank you.

 

[pureinsanity]

You may want to check to see if there is a restriction in a fuel line (rubber hose collapsing inside or kinked) or fuel pressure of the fuel pump. Then also check the ignition timing and the weights in the distributor to see if they are moving freely.

 

[johnkom]

Define: "...hesitating at high speeds." Do you mean bogs down, or backfires? Stuck weights in the distributor will definitely limit the high end.

JK

 

[Sea Ray 220]

It doesn't back fire just slows then speeds up. Best way to describe it is if you moved the throttle back and forth once you hit top speed.

 

[pureinsanity]

Like a surging? Definitely look at your timing and distributor weights. Make sure the weights move freely and the shaft has no play. If all that checks good it may be the electronic pick-up giving problems at high rpm.

 

[Sea Ray 220]

Yes surging is good way to describe it. I just bought the boat a few months ago. I notice the screen on the carb where the fuel line came in was in backwards with the spring pushing it against the hole that fuel comes in. When I switch it around it ran great for a few miles and then started surging again.

 

[Sea Ray 220]

One more thing, the surges didn't happen all time which made me think it be gas flow. When I first got the it ran good with only a few surges. This problem slowly got worse.