High speed jets

[RunninLate]

No not on the Sea Pro but in a 1997 Johnson 115 hp motor that I have on a 1976 Mako 171 Angler.

The last time I had it out the boat would run up to 5500 RPMs and this past weekend I put it in the water and it took forever to get to 4100 RPMs and that was all she would do. When I got back to the house I put some SeaFoam into the tank but did not feel like taking the boat back to the marina again.

I was thinking that the high speed jets might be blocked. Or maybe I lost a power pack on one of the cylinders. In the next few days I will run a compression check on the motor just to make sure that there is nothing wrong with the physical working of the motor. Also I am going to check the spark plugs to make sure the are not black. I just put them in the boat may be a month ago. But to start the motor you need to choke the hell out of it and advance the throttle.

Couple of the symptoms are the motor did not want to idle with no throttle and would never get pass 4100 rpms.

Another question, when I trim up the motor all the way, does the gas stay in the carbs. It seam that I have to reprime the motor when I try to start it again.

I am open to any ideas or suggestions.

[Simple Man]

Sounds like carbs to me. I would get someone that knows what they are doing to rebuild them if it was my boat. Also check out the fuel system and repair/replace/flush as necessary. I assume the boat has been sitting up or doesn't get alot of use?

[RunninLate]

I ran the boat about 4 weeks ago and it ran great. Not sure what happened. I call my tech and they said it would cost an hours worth of labor to rebuild each carb plus parts. I think there are 2 carbs on the motor. It is a 4 cylinder.

I also need to see how hard it would be to pull new fuel lines from the motor to the the tank. I think it is about 6 feet and should not be a problem if there are not any right angle turns.

Will keep you posted.

Thanks,

[Simple Man]

On most every boat I have owned, it's not to bad of a job to run fuel lines as long as you have access to where they connect to the tank. As far as the motor running bad, talk to your mechanic but I had a good mechanic tell me years ago that carbs are only going to last you about 5 years per rebuild depending on the quality of gas used and how much you run the engine (more use equals longer runtime). That's one reason why I have been going with fuel injection motors since 1995 on every boat I own except one and yes I had carb problems with the one exception!

[drock63]

Every time you trim up motor fuel will drain back out of carb bowls so you will need to reprime. Sounds like you could use a good carb cleaning, jets might be plugged. Did you check/change fuel filters and or fuel water separator? Might not be getting the fuel it needs at higher rpms.

[RunninLate]

Drock, The problem was one of the coils was shorting out against the head. For some reason it was put on 180 degrees backward.

But you are right about needing a good carb cleaning. when I trim up the motor I do have to reprime the motor.