View Full Version : Engine convulsing above 2300 rpm

09-22-2008, 12:28 PM
My 1983 mastercraft with a ford 351 has been running great all summer, and just yesterday I started having some engine problems. As soon as I hit about 2300 rpm, the engine started lurching, and the rpms shot up to about 5000, and I could tell I was getting no power, and it would drop back down, accelerate a bit, then shoot back up to 5000 or so. The boat still accelerates fine up till about 2300 rpms, and thats where everything goes wrong.

Any ideas whats going on?

09-22-2008, 12:56 PM
Sounds like a transmission issue:(

09-22-2008, 01:06 PM
Sounds like a transmission issue:(


09-22-2008, 03:46 PM
ugh, so how bad am I looking if its the tranny?

09-22-2008, 03:47 PM
To fix it youself, have it done, or buy a new one?

09-22-2008, 04:16 PM
Mine did something similar at the beginning of summer. All I had to do was add transmission fluid.

09-25-2008, 04:10 PM
So yea, seems like the transmission is screwed, any ideas how much a new one would cost to be installed?

09-25-2008, 05:56 PM
have you tried to rev up the motor out of gear? I'd try this and see if it does the same thing. If so, then it's something w/the motor, and the first place I'd check is the distributor/points/plugs/rotor, etc. If it doesn't do it, then I'd bet it's the tranny. Have you converted to electronic ignition? If you haven't, I'd recommend a mallory elect. ignition kit. Mine worked great. You can call discount inboard marine for transmissions, or see if you can get it rebuilt-that'd be a cheaper way to go.

09-25-2008, 06:50 PM
Depending on which transmission you have (I will guess Borg 1:1) you're looking at anywhere between $1,100 to $2,200. The Borg NEW from skidim is $1,449. You could probably install it yourself.

09-25-2008, 08:19 PM
Call around in your area- there's usually someone nearby that rebuilds these.