Motor problem

[cargotrailer]

Went out with my dad yesterday in his boat and we had the problem described below. Any help would be appreciated.

We putted out of HBSP, past the no wake zone. When he gave it full throttle to take off the motor would only get about 2500 rpm. It was like it was "bogged" down. We stopped and tried several times because it had done this before, but eventually it always straightens out. This time it didn't clear up so we putted over to the main channel and fished a little. About 30 minutes we decided to try again, started the motor, gave it full throttle and took off like nothing was ever wrong. We didn't have any problems the rest of the morning.

120 HP Johnson, I think mid 90's model.

Any ideas?

 

[ArmySarge]

m17glock would be the man to ask.....

 

[Liveliner]

I ain't Glock ... However I can tell you that your primer bulb has check valves that are going bad.  Replace the bulb and fuel lines fron the tank to the engine and solve your problem. If you have good fuel lines and good hose clamps you may just replace the bulb.  You can replace the whole thing just about as cheap as just the bulb. The bulb has a valve that has gotten stiff and does not seal properly allowing your engine to loose it;s prime.  After a while the new fuel and the heat will allow it to run better.  It will only get worse.  Do not get out there and get stranded.

 

[Bubbakat]

Try pumping that primer bulb next time it happens to see if it helps and if it does then it most likely needs replacing. The first thing that always needs to be done is a spark check and compression check. A bogging down symptom gives about the same reaction with fuel or coil breaking down and loosing one cylinder.

 

[hl&s]

I had a problem similar to this last year. I happen to notice after it happened a couple of times that the primer bulb was collapsed. What I found to be the problem was a piece of trash in the thru-hull brass fitting where the fuel line connected. While the engine was running, fuel flow would pull the piece of trash into the fitting and restrict the fuel causing the bulb to collapse. When I cut the engine off, the trash would float back down out of the way. The bulb would pump back up and the engine would run fine until it happened again. I took the fitting off and blew out the trash and haven't had any problems since. If your primer bulb is collapsing, and a new one doesn't fix the problem, check for trash in the lines from the bulb to the tank. A clear glass fuel filter can also help you identify whether you have a fuel supply problem or not as the fuel is visible.

 

[m17glock]

ArmySarge - 9/4/2007 11:35 AM

m17glock would be the man to ask.....

emoQuestion emoQuestion emoQuestion

i have been called a know it all on occasion emoTongue
and some call me Mcgyver emoBigsmile

but i dont recall having an answer to a problem like this
but then again i am still a little fuzzy from pain meds emoDance

 

[hoggerhead]

mine did the exact same thing this year and it was my carb.

 

[hoggerhead]

And also If you have a plunger type choke, it could be worn, and allowing more fuel to the carb than needed.

 

[dtw2]

I would change the fuel line and hand bulb, also replace fuel filter

 

[cargotrailer]

Thanks for all the help. He will be replacing the fuel line and bulb tomorrow, and filter. Hope to get it out on the water sometime. Will let you know how it goes.

Thanks

 

[Bubbakat]

He didn't happen by any chance get hold of some E10 fuel did he. That has caused some problems on some engines. When the fuel exceeds 10% ethanol and it it sets for awhile it will draw water like a magnet and cause the same reaction.

 

[BASSMASTRBW96]

change all fuel lines bubble and everything the nrun mtor with the choke on up and down river till it dies

 

[Bubbakat]

Sounds like the fuel pump may have a bad diaphragm.