Hi, I have a 1988 mercury 9.9hp 2 stroke. Starts ok, idles Ok, seems to get up to top speed when running in a barrel but once behind boat in water it seems to maybe run at half speed at most. This is what I’ve done:
Removed carb, dismantled it all and cleaned and put back together- I’m not a professional mechanic but have rebuilt a number of carbs over the years so I’m fairly sure that I didn’t mess anything up and is working fine.. but can’t guarantee it! Lol
did compression test. 98psi in both, I know it’s a little low but again don’t think that’s my problem
took to a outboard shop and they replace the wires, plugs and the ignition/ black box because they say it didn’t test right.
they say I have no thermostat ( I guess previous owner took it out). They told me that once warm and running at full speed it should run. They also mentioned that maybe the exhaust port may have carbon build up???
bTook it to the lake and same thing no power. Seems that gets to maybe half speed.
took home and pulled the spark plugs and top one was really fouled and bottom was dry and a little brown..
did ohms test on coils and the were in spec , ohms test on trigger was good, Ohms test on stator , white wire to ground is good, white to yellow was low and yellow to ground was low..hmm must be stator then. Replaced stator took to lake and still no power, idles better but it’s very frustrating putting around a lake with no power.. any ideas of what my problem could be? And what I should check and test next? I’m out of ideas and loosing a lot fishing days with my boys due to this problem and would really appreciate and advice. Thanks
Removed carb, dismantled it all and cleaned and put back together- I’m not a professional mechanic but have rebuilt a number of carbs over the years so I’m fairly sure that I didn’t mess anything up and is working fine.. but can’t guarantee it! Lol
did compression test. 98psi in both, I know it’s a little low but again don’t think that’s my problem
took to a outboard shop and they replace the wires, plugs and the ignition/ black box because they say it didn’t test right.
they say I have no thermostat ( I guess previous owner took it out). They told me that once warm and running at full speed it should run. They also mentioned that maybe the exhaust port may have carbon build up???
bTook it to the lake and same thing no power. Seems that gets to maybe half speed.
took home and pulled the spark plugs and top one was really fouled and bottom was dry and a little brown..
did ohms test on coils and the were in spec , ohms test on trigger was good, Ohms test on stator , white wire to ground is good, white to yellow was low and yellow to ground was low..hmm must be stator then. Replaced stator took to lake and still no power, idles better but it’s very frustrating putting around a lake with no power.. any ideas of what my problem could be? And what I should check and test next? I’m out of ideas and loosing a lot fishing days with my boys due to this problem and would really appreciate and advice. Thanks
