John Locke
New Member
My craft runs great for about 4 to 5 miles, then it starts starving for gas. Initially it slows down from 49mph (top speed) to ~43mph, then ~40mph, then it just bogs down to practically no power and can't plane. Sometimes even with the choke on 100% and the throttle wide open, it barely keeps running to do 5mph, when normally if I pull on the choke it kills the motor because of too much fuel. However it will idle forever, like a champ, so small amounts of fuel are provided to adequately support idling. You can putt around wakeless at idle forever. Both times I've taken it out in the last week, it runs great for about 4 or 5 miles, but after warming up it starts to starve for fuel, ending the day. The cooling water is flowing fine out the squirt nozzle in the rear like normal, so that eliminates potential overheating.
I've done the following:
1. Replaced the carburetor, it's brand new as of 3wks ago. The original carb was toast inside after leaving it in storage 4yrs. However, before I replaced the carb, 4yrs ago, before I put it in storage, the craft had the IDENTICAL problem that I never solved, which is why I haven't ridden it in 4yrs (along with other reasons). I thought maybe a new carb would fix it, but no joy. It has the exact symptom as 4yrs ago with the original carb. That seems to indicate it's not a carb problem.
2. Replaced all fuel lines, including both breather lines and the fuel pump pulse line from the crankcase.
3. Checked the pop off valve and the one way intake air valve to the gas tank, they seem to work fine. When the symptom starts, I've also taken the gas cap off to eliminate the possibility of a vacuum in the gas tank, verifying the one way air intake valve was working OK.
4. I disassembled the petcock gas selector valve and cleaned it out really good. With a full tank of gas, the bogging symptom exhibits itself in both positions, ON and RESERVE.
5. I removed the internal gas tank intake tower to inspect the integrity of the internal tank filter, looking for possible obstructions, but no joy.
6. After installing the new carb, and failing on my first lake test, I removed the brand new carburetor and checked the internal tiny filter located in the diaphragm pump. It was 100% clear.
I think my fuel starvation problem has something to do with heat, but that's only a guess because it runs great for about 10 or 15 minutes after sitting all night. It's consistent at exhibiting the fuel starvation symptom from one day to another day. However this problem cannot be duplicated in a shop, as it take a long time (15-20 minutes) for it to fail at full throttle. I don't think a test tank can accommodate such a long full throttle test.
Does anyone know of something else to check?
I'm getting really good at removing the carburetor, but it's getting a bit old, having no positive results.
I've done the following:
1. Replaced the carburetor, it's brand new as of 3wks ago. The original carb was toast inside after leaving it in storage 4yrs. However, before I replaced the carb, 4yrs ago, before I put it in storage, the craft had the IDENTICAL problem that I never solved, which is why I haven't ridden it in 4yrs (along with other reasons). I thought maybe a new carb would fix it, but no joy. It has the exact symptom as 4yrs ago with the original carb. That seems to indicate it's not a carb problem.
2. Replaced all fuel lines, including both breather lines and the fuel pump pulse line from the crankcase.
3. Checked the pop off valve and the one way intake air valve to the gas tank, they seem to work fine. When the symptom starts, I've also taken the gas cap off to eliminate the possibility of a vacuum in the gas tank, verifying the one way air intake valve was working OK.
4. I disassembled the petcock gas selector valve and cleaned it out really good. With a full tank of gas, the bogging symptom exhibits itself in both positions, ON and RESERVE.
5. I removed the internal gas tank intake tower to inspect the integrity of the internal tank filter, looking for possible obstructions, but no joy.
6. After installing the new carb, and failing on my first lake test, I removed the brand new carburetor and checked the internal tiny filter located in the diaphragm pump. It was 100% clear.
I think my fuel starvation problem has something to do with heat, but that's only a guess because it runs great for about 10 or 15 minutes after sitting all night. It's consistent at exhibiting the fuel starvation symptom from one day to another day. However this problem cannot be duplicated in a shop, as it take a long time (15-20 minutes) for it to fail at full throttle. I don't think a test tank can accommodate such a long full throttle test.
Does anyone know of something else to check?
I'm getting really good at removing the carburetor, but it's getting a bit old, having no positive results.