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Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I lose RPMs on my right engine at rmp's over 3000. Then it

Customer Question

I lose RPMs on my right engine at rmp's over 3000. Then it will regain the rpm's and will continue in this manner. It feels as though it is being starved for air or even a fuel problem.
Submitted: 2 years ago.
Category: Boat
Expert:  Tan replied 2 years ago.
Hello. My name is***** will be helping you. This is a fuel starvation issue. This will require connecting a vacuum gauge on the suction side of the fuel pump. Usually just before the fuel filter on the engine. Tee in to the fuel line just before the fuel filter and connect the vacuum gauge. Run the boat watching the vacuum gauge. What does the gauge read?
Expert:  Tan replied 2 years ago.
Here is a diagram to follow. http://ww2.justanswer.com/uploads/jacksparrow1956/2011-06-08_174123_fuel_vacuum_test.jpg
Customer: replied 2 years ago.
I'll try that when I'm at my boat, this weekend was cancelled due to strong storms this weekend at Grand Lake, Oklahoma.
Expert:  Tan replied 2 years ago.
Ok let me know what you find. Do you understand the procedure?
Customer: replied 2 years ago.
what should the guage read that if I have a problem what is the fix?
Expert:  Tan replied 2 years ago.
The gauge should read less than 2 " of vacuum. Anything more is an indication of a fuel restriction. The restriction could be screen on the end of pick up tube, blocked fuel tank vent collapsing fuel line. If you see allot of air bubbles then you have a air leak between the gauge and the tank. It could even be a clogged fuel filter. Some SeaRays had a fuel filter right at the top of the fuel tank.
Customer: replied 2 years ago.
Thanks Tan, I'll let you know.
Expert:  Tan replied 2 years ago.
Your welcome. If the gauge is below 2" of vacuum we need to check fuel pressure. I will need the engine serial number to get the specification. From you description it is fuel starvation. Keep me posted to your findings and we can continue with troubleshooting.