Im fairly new to this boat and would appreciate your opinion on what to do next. The motor in question just had the top end rebuilt. It has good compression. Around half throttle I hit 4k rpm...any more throttle and still 4k. dr honda advised someone else with a similar problem to pull the choke at 4k. I did that today and the motor stalled immediately. If I remember right that meant there is an excessive load on the engine. Any suggestions on where this rookie should start. Thx
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nothing past 4000 rpm...please help
- Thread starter gcha1727
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yes its off the trailer, in gear on the lake and nothing past 4k. Throttle work smooth. Its prob at half throttle when I get to 4k. I do see the linkage moving on the carb when tryin to accelerate past 4k. I then pulled the choke and the motor shut off immediately. It will start back up. I dont have any other starting/idling/running problems until 4k. The other motor works fine.
97sportser
New Member
Same issue!!
I have a 97 sportster that I am having the same issue with. I have don't the following to no avail.
1 - Checked the in-line fuel filter and it was full of crap so I cleaned it.
2 - Removed the very small fuel filter from inside the carb and it was clean (like new)
3 - Removed both jets from carb and both were clear and clean
4 - Removed the baffle from the gas tank and it was clean
5 - checked carb valve action and both are in sync.
6 - Replaced the spark plugs with NGK's
7 - The new plugs were wet with a dark liquid when I pulled them back out after running, so I adjusted the carbs to run a little more lean.
Engine still bogs down at half throttle!! Please Help.
I have a 97 sportster that I am having the same issue with. I have don't the following to no avail.
1 - Checked the in-line fuel filter and it was full of crap so I cleaned it.
2 - Removed the very small fuel filter from inside the carb and it was clean (like new)
3 - Removed both jets from carb and both were clear and clean
4 - Removed the baffle from the gas tank and it was clean
5 - checked carb valve action and both are in sync.
6 - Replaced the spark plugs with NGK's
7 - The new plugs were wet with a dark liquid when I pulled them back out after running, so I adjusted the carbs to run a little more lean.
Engine still bogs down at half throttle!! Please Help.
Thx for passing along that info. Does your boat have 1 or 2 motors? Is it the 787? Im determined to figure this out and will post any more info I come across. Ive had alot of experience in the past of auto electrical but none with engine repair, let alone 2-cycle. Also this is my 1st boat/watercraft. I had a thought that maybe its possible the motor Im having a problem with isnt actually in gear. I always have both running in the water because Im afraid of water backfeeding into the other. so when im in forward and throttle up maybe 1 is actually pushin the boat and the other is in nuetral. Ive read that the rev limiter stops it from revving past 4k in nuetral so I think the story could add up. Or maybe Im way off and its not poss. Anyway Im heading in that direction next unless someone advises somewhere else. Anyone else have any ideas???
can anyone tell me what actually engages when going from neutral to forward. It appears as though all the linkages are working properly when using the shifter. I checked the wire going to the computer from the shifter and is working properly. So when the computer sees the shifter forward does it then send a signal out to a part that creates propulsion? I was going to test the trigger coil but Im unsure if Im getting off track... and also6-pin adaptor they suggest using I obv dont have and Im unsure which wires to test. Im assuming that my spark is ok since the idle is good through 4k. So at this point if anyone can what I should look for next I would greatly appreciate it...Thx
Dr Honda
Well-Known Member
When you go from F-N-R.... all that is happening, is the bucket behind the pump drops down. But... there is a safety switch to keep it from reving pas 3500 rpm if not in Forward.
If it was cavatation... the engine would rev up, an not make any (or very little) thrust.
If it was fuel related... it would either die from lack of fuel... or it would cough and sputter (and smoke, and foul spark plugs) from being too rich.
I'm going to have to guess that it's an ignition problem.
Do you have 800 or 720 engines? (don't remember off the top of my head)
If it was cavatation... the engine would rev up, an not make any (or very little) thrust.
If it was fuel related... it would either die from lack of fuel... or it would cough and sputter (and smoke, and foul spark plugs) from being too rich.
I'm going to have to guess that it's an ignition problem.
Do you have 800 or 720 engines? (don't remember off the top of my head)
DR Honda thx for the response. I just took it back to the water to check more things. When I 1st put boat in water I did find a leak By what I think is the carbon seal. Were the drive shaft leaves the engine comp. Also both motors work identical to around 4k. I tried one at 4k and left the other one at lowest rpm-result 7 mph. Reversed the 2 motors and got same result 7 mph. But when accelerating with bad motor past 4k I hear or feel nothing kicking like the good motor. Prob rev limiter as you suggested. I thought I read somewhere I can disconnect limiter but I didnt have that info with me at the time. Im thinkin of heading back at shortly to try it. Do you think this could also be a jet pump issue?? It looks like all the parts on the drive shaft were recently replaced. The impeller looks good . 787s
Dr Honda
Well-Known Member
If it was the neutral safety switch... both engines would have the issue of not reving up.
Since it has 800 engiens... I'm going to say that your pick up coil (in the mag assembly) is going bad, or the mount is ready to break, and it's just picking up a weak signal. The faster the engine revs... the worse the signal will get. (less magnetic dwell)
Unfortunately, this may be a hard thing to chase down without being in front of the engine.
One more thing. Do you have 2 batteries, or one from the factory? Seadooya has been seeing a bunch of strange things when the regulators go bad. If you have 2 batteries... check the battery on the engine that is cutting out with a volt meter. Start it up, and try to rev it to 5000 rpm's. If you see more than 14.5v... the high voltage is making your CDI go crazy.
Since it has 800 engiens... I'm going to say that your pick up coil (in the mag assembly) is going bad, or the mount is ready to break, and it's just picking up a weak signal. The faster the engine revs... the worse the signal will get. (less magnetic dwell)
Unfortunately, this may be a hard thing to chase down without being in front of the engine.
One more thing. Do you have 2 batteries, or one from the factory? Seadooya has been seeing a bunch of strange things when the regulators go bad. If you have 2 batteries... check the battery on the engine that is cutting out with a volt meter. Start it up, and try to rev it to 5000 rpm's. If you see more than 14.5v... the high voltage is making your CDI go crazy.
If there isnt a way to test the pickup coil without the adaptor, Im thinking maybe I can swap out the coil from the other motor to check it. Is it alot of work to pull those out? Or would it be possible to create a jumper harness from the good motor magneto to the wires on the bad side?
Finally over 4k!!!! Well kind of. I brought home from the lake today started both motors with hoses attached. While running I shifted forward , pushed up throttle and to my suprise it went past 4k. I did a couple short burts to 6-7k. I felt like I hit the lottery. So now I can spend another night on the forum trying to find a similar thread. Any ideas out there???
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