300/440/550 not enough spark at high rmps??

B

Bluegill

Location
South Haven, Michigan
I have done a search of all the threads and am coming up empty handed....My 91 550sx seems to not get enough spark when i rev it up, it just bogs and backfires a bit. It idles great and starts easily, it just wont run much higher than idle. I first thought carburation, but now I am pretty convinced its electrical. Any Ideas? Thanks.
 
C

chad550

Location
Galvez, Louisiana
I just went through this with my 550/650 conversion ski. It was doing the same thing. Then noticed the exhaust pipe was getting extremely hot. Got home took waterbox out and the baffle in side had broken loose, blocking the exit in box. I pulled the box apart, removed the loose baffle and glued the box back together. Will try it tommorow, but more than sure thats the problem.
 
B

Bluegill

Location
South Haven, Michigan
thanks for the heads up chad, ill try that tomorrow night. I cut .5 inch off the ends of the plug wires and put the boots back on a few minutes ago, but its still about the same.

What exactly does the waterbox do? Thanks again
 
C

chad550

Location
Galvez, Louisiana
The waterbox acts as a muffler. Just check exhaust pipe and head are not getting real hot (water sizzles when put on pipe) when you are trying to rev it up. If not then the waterbox is not your problem.
 
wetjet701

wetjet701

Always On
Check your timing and make sure your getting plenty of fuel also it could be bad reeds if it's a reed motor
 
B

Bluegill

Location
South Haven, Michigan
it looks like it might be either my pulser coil or my exciter coil. I just ordered both from dennis kirk so we will see. I talked to a guy who had my exact same problem, so i am going to put in some new coils. what is pissing me off is I could have bought a pretty sweet ski for the amount i have into this dumb 550. too bad i am too stubborn to stop now...this ski will run.
 
B

Bluegill

Location
South Haven, Michigan
Just in case someone has the same problem with their ski as i did. I turns out the problem was either the pulser coil or the exciter coil. I changed both of them because they are such a pain in the butt to get to. Runs great now, thanks for all the help guys.
 
You must log in or register to reply here.
Top Bottom