KDMatt
Seaman Apprentice
- Joined
- Aug 8, 2009
- Messages
- 33
This is a carb'ed motor that was rebuilt/tuned a few years ago, and I'm having a recurring/stubborn surging and hesitation issue.
It started surging and hesitating a bit through the hole-shot at the end of last season, but smooths out on plane.
This season I replaced the fuel tank with a brand new moeller one, added a 10-micron screw-on fuel filter, new primer bulb, replaced both fuel pumps, and took apart and cleaned out the carburetors. I changed the plugs too. It ran great for a few hours -- thought I'd fixed the problem -- but then the issue returned.
I cleaned the carburetors again last week, but it's still doing it.
I'm up on vacation with my family right now, so the boat's in the water.
I have no trouble starting the motor, and while it stumbles a bit through the low RPM range, the hesitation only becomes an issue when I go from idle speed to open throttle... If I ease into the higher-RPM's it's not as noticeable.
I could use a few suggestions on where to turn next. Ignition? Would a vacuum leak cause issues like this? Incorrectly adjusted carbs? Could my floats be set wrong? There are some adjustment screws on the sides of the carbs -- do those ever need periodic tweaking?
I'm a car guy, and normally live in the realm of 4-stroke and EFI, so this is all a little foreign to me still. Any help anyone can offer is appreciated. Thank you!!
1999 Yamaha P150 TLRX
It started surging and hesitating a bit through the hole-shot at the end of last season, but smooths out on plane.
This season I replaced the fuel tank with a brand new moeller one, added a 10-micron screw-on fuel filter, new primer bulb, replaced both fuel pumps, and took apart and cleaned out the carburetors. I changed the plugs too. It ran great for a few hours -- thought I'd fixed the problem -- but then the issue returned.
I cleaned the carburetors again last week, but it's still doing it.
I'm up on vacation with my family right now, so the boat's in the water.
I have no trouble starting the motor, and while it stumbles a bit through the low RPM range, the hesitation only becomes an issue when I go from idle speed to open throttle... If I ease into the higher-RPM's it's not as noticeable.
I could use a few suggestions on where to turn next. Ignition? Would a vacuum leak cause issues like this? Incorrectly adjusted carbs? Could my floats be set wrong? There are some adjustment screws on the sides of the carbs -- do those ever need periodic tweaking?
I'm a car guy, and normally live in the realm of 4-stroke and EFI, so this is all a little foreign to me still. Any help anyone can offer is appreciated. Thank you!!
1999 Yamaha P150 TLRX
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