Tweet
Hello,
I repowered this season with a used outboard (1998 OX66 225hp) with a zero hour powerhead. Went through the 15 hours of low rpm (varied) use and am now at about 30 hours total. From day one It has idled quite high (1200 rpms) and had a stumble in the range from 1200 rpms up to where the boat starts to climb up on plane. You cannot move the boat at high rpm non-planing speeds - it bogs, coughs and stumbles. Additionally WOT with motor trimmed til it just starts to cavitate is 4500 rpms. Fuel consumption also seems to be higher than I would expect (have a Navman fuel monitor and have checked calibration). 14gph at 27 mph is worse than what I got with the old carbed motor. I also can see raw fuel or oil in the water when I return to the dock. It seems to be coming from the exhaust.
Thus far I have replaced the O2 sensor (the first one fell off, and broke the cross tube during the break-in period), replaced the VST filter and o-ring, ran a Seafoam shock treatment through it. The plugs were new, and don't look bad. the boat previously had a 96 carbed Saltwater Series II that had a host of ethanol issues. I assume that alot of the tank crud has been flushed out already as we have had ethanol in CT now for 3 seasons and the boat was used quite a bit (the Racor 90gph10micron filter has been replaced each season).
I also had a mechanic look at it. In addition to replacing the VST filter, one of the things he did was to pull the low pressure pumps and check them by squeezing the primer bulb. He said they were ok and noted that they looked new.
I will be borrowing a fuel pressure gauge soon to monitor the pressure when the stumble occurs.
The O2 sensor was most likely not reinstalled properly when the powerhead was put back on. Is it possible that the throttle position sensor may be out a wack as well? I assume that would be removed to do a powerhead exchange. Would it need to be tested and adjusted when it was reinstalled?
The dealer that I bought this from has been no help. I have a 90 day warranty, but he says it does not cover fuel or electrical sensor issues. I can't get the boat to him to diagnose as he is in another State (no trailer) but he claims it is probably fuel related (telephone diagnosis).
I have searched the forums, and did not really find a problem like this one. Anybody have any thoughts?
I repowered this season with a used outboard (1998 OX66 225hp) with a zero hour powerhead. Went through the 15 hours of low rpm (varied) use and am now at about 30 hours total. From day one It has idled quite high (1200 rpms) and had a stumble in the range from 1200 rpms up to where the boat starts to climb up on plane. You cannot move the boat at high rpm non-planing speeds - it bogs, coughs and stumbles. Additionally WOT with motor trimmed til it just starts to cavitate is 4500 rpms. Fuel consumption also seems to be higher than I would expect (have a Navman fuel monitor and have checked calibration). 14gph at 27 mph is worse than what I got with the old carbed motor. I also can see raw fuel or oil in the water when I return to the dock. It seems to be coming from the exhaust.
Thus far I have replaced the O2 sensor (the first one fell off, and broke the cross tube during the break-in period), replaced the VST filter and o-ring, ran a Seafoam shock treatment through it. The plugs were new, and don't look bad. the boat previously had a 96 carbed Saltwater Series II that had a host of ethanol issues. I assume that alot of the tank crud has been flushed out already as we have had ethanol in CT now for 3 seasons and the boat was used quite a bit (the Racor 90gph10micron filter has been replaced each season).
I also had a mechanic look at it. In addition to replacing the VST filter, one of the things he did was to pull the low pressure pumps and check them by squeezing the primer bulb. He said they were ok and noted that they looked new.
I will be borrowing a fuel pressure gauge soon to monitor the pressure when the stumble occurs.
The O2 sensor was most likely not reinstalled properly when the powerhead was put back on. Is it possible that the throttle position sensor may be out a wack as well? I assume that would be removed to do a powerhead exchange. Would it need to be tested and adjusted when it was reinstalled?
The dealer that I bought this from has been no help. I have a 90 day warranty, but he says it does not cover fuel or electrical sensor issues. I can't get the boat to him to diagnose as he is in another State (no trailer) but he claims it is probably fuel related (telephone diagnosis).
I have searched the forums, and did not really find a problem like this one. Anybody have any thoughts?
Comment