Thread: throttle surge
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Old 08-22-2013, 08:40 PM
StrmChzr StrmChzr is offline
TT Enthusiast
Join Date: Jan 2012
Boat: 2005 XStar
Location: Midwest
Posts: 209

Previous post was "accurate" for exactly one month and then the surging started again while on week vaca at TRL in late July. When surging returned, it was not remedied by filling fuel tank full. I changed the fuel filter (old filter was little dirty, but not bad) and engine still surged.

Long story short, a MC dealer friend let me borrow his fuel pump compression gauge which lead us to the culprit. At key up, fuel pump pressure was 35psi (should be 50-60psi for my pump) which was suspicious, but when engine started it immediately jumped to 55psi. I had to launch boat and run it down lake to cause surging and SURE ENOUGH, engine surging directly correlated with compression gauge dropping down to <25psi.

I had replaced fuel pump with auto parts store carter pump last summer, so I decided to take a 4 c-note upper cut to the chin and purchase a new MC fuel pump (complete fuel pump and hardware) this time. The day the MC pump was suppose to arrive, Dave mentioned he had seen black tubing kink inside fuel pumps on other MC's and recommended I check that before installing MC fuel pump system. He gave me a $0.50 corrugated tubing to replace the black thicker tubing inside the fuel pump.

VOILA - it worked!! Thankfully, the owner of Ski-N-Sports didn't mind keeping the new MC fuel pump and it only ended up costing me 60 bucks for the overnight shipping charge.

A few weeks later, I saw the fuel pump thread in which the "hose" issue is addressed with great info and pics on the first page of post.
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