Home › Forum › Ask A Member › 1999 johnson 9.9
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fleetwin.
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April 1, 2024 at 10:39 am #286432
hey guys, i need help . my motor would idle good and run good at low speed. once i gave it full throttle, it would start lugging along, sometimes picking up fulll speed for a few second and dropping back to a slower speed. it did not seem to miss at a lower speed. i have a parts motor but i am not sure if all the parts are good. first thing i did was rebuild carb. took to lake and no difference. changed coil pack and spark plug wires. have good spark. took fuel line off carb and turned motor over. i have a good amount of fuel como\ing out but do not know if it is enough. now my motor will not start (idle). I did get it running by increasing the throttle but to shift into gear i have to have my motor idle. My thoughts are that if it was running at higher throttle, my fuel pump and electrical are good. i took the carb off and blew out the idle valve, nothing changed. i put my original 9.9 carb on ( i’ve been using a 15) and still would not start or idle. i have the fuel adjustment screw out 6 turns. i have gone both ways a 1/4 turn at a time with no success. i keep thinking its a fuel problem but am not sure.do you guys have any tricks to help me pinpoint my problem? PLEASE HELP! THE CRAPPIE ARE BITING
April 1, 2024 at 10:53 am #2864336 turns out is very rich. The OMC manual for that engine says the starting point is 2 1/2 turns out.
April 1, 2024 at 11:00 am #286434I think that if you have not already done so I would check for loss of compression due to a blown head gasket ; perhaps with the associated water intrusion.
I would also want to check for a blown fuel pump diaphragm although I guess that’s unlikely since you’ve checked fuel flow to the carb. Still I would check that. The prime bulb should firm up hard once the bowl is full.
Maybe something stuck in one of the reeds?
At one point of your ownership of this motor it ran 100%? These issues came about out of the blue?
April 1, 2024 at 3:41 pm #286439Yeah, so you have changed the carb to a 15hp carb and it still runs the same? Or, it will not run at all with the 15hp carb? I guess at this point I would reinstall the 9.9/original carb. This issue could be many things, tough to judge by your comments. I don’t want to send you off in the wrong direction. Most issues are relatively simple until we dig too deep and get confused…. Any way you can post a video of the engine misbehaving? I know it probably won’t fit here, but you can post a link….
April 1, 2024 at 6:19 pm #286448i have had the 15 carb on for 2 years and it has been great. i just put the 9.9 carb back on to rule out the a bad carb. there is a shut off on top of the solenoid for the primer. i have had this motor for 5 years and never touched it. while checking this out i found out this is in the off position. my spare motor is also in the off position. i do not understand how the primer works shut off. could this affect the carb?
April 1, 2024 at 7:53 pm #286451Johnson / Evinrude primer solenoid (youtube.com)
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April 3, 2024 at 5:40 pm #286492i have had the 15 carb on for 2 years and it has been great. i just put the 9.9 carb back on to rule out the a bad carb. there is a shut off on top of the solenoid for the primer. i have had this motor for 5 years and never touched it. while checking this out i found out this is in the off position. my spare motor is also in the off position. i do not understand how the primer works shut off. could this affect the carb?
OK, so this is a remote electric engine? So it has the electric primer valve instead of an actual choke? If so, that could be your problem. If the primer is stuck open/leaking somehow the engine will run rich, especially at idle, will probably be too rich to run. You can simply pinch off the little primer hose on top of the carb to rule out/confirm that possibility (after getting the engine running first so it will not need the primer to start).
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