yamaha 250 1999 problems

[shane73]

Just purchased a 1999 yamaha 250 saltwater series that the owner said had thrown a rod.. I took the head gaskets off and had a friend spin the thing at the top of the motor to make the pistons move and all moved fine, even with me putting pressure on them.. the prev. owner said it was shaking badly but was still running when he put it up. any idea where to start trying to fix this or should I brind it to the mechanic and get a price to go through the whole thing? OH AND THE PROP SHAFT IS BENT JUST A LITTLE.,.. THANKS FOR ANY ADVISE YOU CAN GIVE.

 

[getusummm]

Re: yamaha 250 1999 problems

How much is just a little?

 

[robert graham]

Re: yamaha 250 1999 problems

maybe the bent prop shaft and prop caused shaking due to imbalance and he just thought he threw a rod. maybe just repair lower end/shaft/prop? good luck!

 

[shane73]

Re: yamaha 250 1999 problems

Well I brought the motor to two mechanics who said it wasn't worth fooling with.. got it home and started it today and let it run for 10 seconds or so with no problem... I just find it hard to believe that a motor that starts up and runs at the turn of the switch isn't worth fixing. sounds to me like they just didnt want to fool with it... so I'll try to find another "mechanic" that might can help me out. The motor was stalling out or missing or anything. I do know that I need a couple of head bolts for it that appear to be too long to fit at the bottom of the left head cover. No luck on that so far either.. anybody got any Ideas?

 

[Islandbrah]

Re: yamaha 250 1999 problems

I would start at a compression test. If you have a busted rod you will find it. Remove all plugs as not to get bleed over. As far as the shaking Does it shake in Neutral? Does it increase with throttle? take the prop shaft out of the equation. I run a 2000 ox66 250 on my Aerotek and I have a little vibration at idle. It pans out once under load. These motors do Idle on the jerky side, however not in the excess that you describe. I had to clean my o2 sensor and it smoothed considerably.

 

[rodbolt]

Re: yamaha 250 1999 problems

remember on that motor there are several different lengths of head bolts, all MUST be in the correct hole.
the factory yamaha manual will actually show a picture and bolt lengths.