94 yamaha 250 with bad miss

[jimbo0]

I have a motor that has a rebuilt powerhead on it. After I got it installed I took a can of pure gas and run the motor all good with the precision blend. I then premix the gas in the tank to get the 25:1 ratio for break in. the port side of the moter does not work now. We are getting spark to the cylinders and fuel.

Any help, Thanks in advance. Oh ya has YMIS.

Jim

 

[jimbo0]

Re: 94 yamaha 250 with bad miss

Is it possible that the YMIS is going bad? I was pulling plug wires off and it seems to be one side of the motor. With the plug wire off you can see the spark on the plug, but when I pull the plug out it looks wet.

I don't know maybe the carbs are the problem.

Anyone.

Jim

 

[jimbo0]

Re: 94 yamaha 250 with bad miss

You know I failed to mention the fact that I had crossed the batt cables when installing some new cables the day before I had problems. It blew out the 80A fuse and I replaced it but I fear it might have done something worse than just blow the fuse but I don't know.

I am in the military and I'm trying to finish this project boat before going back to Iraq in a few weeks. All of the shops around here, Statesville NC, are slammed and can't get to it for a few weeks.

I feel pretty stupid having done that with the cables, I guess getting in a hurry doesn't pay!

Jim

 

[jimbo0]

Re: 94 yamaha 250 with bad miss

Finally got a shop that could take on my work fairly quick, and he said I would more than likely need a rectifier and powerpack to start off with. He said they would test the stuff to see if I fried it. We'll see.

Jim

 

[jimbo0]

Re: 94 yamaha 250 with bad miss

OK Guys, I got the boat back and it turns out I was lucky that I did not do any damage to the rest of the charging system. It was just the rectifier that had to be replaced.

Maybe nobody on here knew what happens when you hook up your battery cables backwards, I don't know. I hope this can help somebody else if they make the same stupid stupid mistake I did.

Jim

 

[jjdluz]

Re: 94 yamaha 250 with bad miss

did change rectifier help?is problem fixed?thanks.

 

[rodbolt]

Re: 94 yamaha 250 with bad miss

as a master yamaha tech I probably know as much about the V76 carbed ign than most. however I cant see the connection between the charging system and the ign system.
but I am glad it works.