Tweet
On my way back to the boat ramp this past Friday (Tampa/Little Cochroach Bay), I slowed down to idle to secure some loose gear. As I attempted to get back underway, my 90HP engine (Mod #90TLRB) started running very rough and sputtering and the boat (17ft Sea Pro) would not get on plane when normally it jumps right out of the water. After verifying I hadn't picked up something in the prop and the engine wasn't overheating, I revved it in neutral but it still missed and sputtered. Luckily I was only a couple of miles out and was able to "limp" back to the boat ramp at about 1/4 normal cruise speed with the engine sounding rough. As I approached the ramp at idle speed, the engine sputtered/sneezed and conked out a few times but I was able to safely dock and load it on the trailer.
The next day I pulled the spark plugs and they all looked good with no carbon buildup or discoloration. I then pulled the fuel filter/water separater and dumped the fuel in clear plastic container. There was no sign of any water or other contaminates in the fuel. I also installed a new fuel/water separator.
I then pulled and disassembled each carburator thoroughly cleaning using decarb spray and compressed air. The only item I could not disassemble were the brass hexagon shaped "Valve Seats" located to the right of the Main jet/nozzle and Pilot jet (see attached pics). After reassembly and putting the carbs back on, setting the idle screws open at 1-1/2 turns, and verifying no fuel leaks after squeezing primer ball, I started the engine. Unfortunately, it still runs rough and stalls.
Note this was the first time I had the boat out after about 3 months. But I always start and run the engine at idle (with water hose connected) at least every other week when not regularly used. I also treat the gas with Startron to neutralize ethanol issues. That morning I added about 17 gallons of new premium fuel to top off the 30 gallon fuel tank. Given these facts, I don't think the problem is fuel contamination or a carb issue.
Could the fuel pump be bad and is there a way to test it? Any other ideas as to what might be causing this problem?
Thanks!
The next day I pulled the spark plugs and they all looked good with no carbon buildup or discoloration. I then pulled the fuel filter/water separater and dumped the fuel in clear plastic container. There was no sign of any water or other contaminates in the fuel. I also installed a new fuel/water separator.
I then pulled and disassembled each carburator thoroughly cleaning using decarb spray and compressed air. The only item I could not disassemble were the brass hexagon shaped "Valve Seats" located to the right of the Main jet/nozzle and Pilot jet (see attached pics). After reassembly and putting the carbs back on, setting the idle screws open at 1-1/2 turns, and verifying no fuel leaks after squeezing primer ball, I started the engine. Unfortunately, it still runs rough and stalls.
Note this was the first time I had the boat out after about 3 months. But I always start and run the engine at idle (with water hose connected) at least every other week when not regularly used. I also treat the gas with Startron to neutralize ethanol issues. That morning I added about 17 gallons of new premium fuel to top off the 30 gallon fuel tank. Given these facts, I don't think the problem is fuel contamination or a carb issue.
Could the fuel pump be bad and is there a way to test it? Any other ideas as to what might be causing this problem?
Thanks!
Comment