200hp Saltwater Series 2 Fuel Problem?

I just bought a boat 2 weeks ago and the motor has been running great until last Saturday. The motor still runs great at 3/4 throttle and a little higher but when I open it all the way it runs good for about 30 sec. to a minute but then boggs down badly. The motor does not die if I pull the throttle back and it picks right back up and runs great again. Someone suggested that I bought bad gas but I have a hard time seeing how that will only affect it at certain throttle points. Does anyone have any suggestions? I would appreciate any input to this problem.

Thanks

[jb123]

what year is it

It's a 1999

[jb123]

most likely need the carbs cleaned but you can try running with an auxillary tank, ball and hose first.

[TimS]

Sounds like it may not be getting enough gas at full throttle. Check or replace any fuel filters if you have not done so already. Then check the primer bulb to see if it is soft - some of them collapse and shut off the fuel flow. Have a helper keep an eye on it while you bring the boat up to full throttle - they could even try a few pumps and see if that makes a difference. Or running on a separate tank will be a good test too.

Tim

I checked the fuel filter on the motor and it looked fine and I am going to check the other filter on the boat today. I will also try and run on an aux tank, ball and hose sometime this week. If there is water in the tank can I run it through and refill with good gas or will this damage the motor?

[jb123]

hopefully if there is water in tank your water SEParator will filter it out.

The results

I took the boat out yesterday and ran it for about an hour. I tried to replicate the problem but it ran great. I did not have to do anything and the boat ran fine at full speed. Kind of strange. I wonder if the fuel needed some time to sit? Any thoughts?

A couple of thoughts for the future. Yammies are pretty sensitive to water. If you have water in the system or are low on oil, they system is set up to restrict the maximum engine rpm's. This would give you intermittent RPM problems. Take the engine cover off. Probably on the port side of the engine you will see a clear fuel bowl. There is probably a red "ring" inside. This ring should be at the bottom of the bowl. If there is water in your filter the ring will float. You might also consider adding a separate water/fuel separator filter between the gas tank and the engine. Easy to do and very effective. They make them with a clear bottom and a drain so if it fill with water you can drain the filter.