Motor Troubles

[BigNiner19]

I knew it was to good to be true. After the rebuild I've put probably 100 hours+ on the motor. Motor still runs, and I dont think anything severe is wrong with it. But its struggling at idle, running pretty rough, even with a little vibration. This is in gear at idle or in nuetral.

But once you give it some gas and get it up on plane, it runs great and the motor sounds like it always did before. Why does it sound so bad at low RPM's?

I put it on the hose, and I was actually able to hear it miss pretty frequently while idling on the hose. Do I need to rebuild the carbs? Could something else be wrong?

Cory

 

[HighTrim]

Re: Motor Troubles

Could be. Try spraying some pre mixed fuel into the carb throats at idle and see if she pick up some.

 

[tashasdaddy]

Re: Motor Troubles

have you checked you spark at idle?

 

[BigNiner19]

Re: Motor Troubles

have you checked you spark at idle?

No I need to do that. But would the spark get better at WOT or cruise? If it did have bad spark at idle?

I'm going to investigate more tomorrow. Im gonna start with the plugs, and go from there. I have a bad feeling I need to take the carbs off and rebuild them though. That is the only thing that hasn't been done on this motor....I cleaned them, but did not rebuild the carbs.

Hightrim,

I tried pumping the ball while at idle and it didnt seem to help much. It still idle'd rough and wanted to die.

Cory

 

[HighTrim]

Re: Motor Troubles

Get a spray bottle filled with pre mixed fuel and spray it into the carb throats. Likely that they need a bath/rebuild. Spitting back, sounding like a mild backfire, indicates a carb slow speed restricted jet..... something causing a lean carburetor scenario.

 

[mikesea]

Re: Motor Troubles

I posted about this before.We found some of the 3 cyl.engines,after rebuild with oversize pistons needed the air bleed jets made smaller.They are located on the front of the carbs,if you have them,you can experiment with eng running take a toothpick and gently insert,see if idle comes up,the fix is checking on the jet which is removable with screwdriver,look for the size stamped ,you may need a magnifyer,or get a tiny set of drillbits and see what fits,that will be your size,then melt solder into the back of jet and redrill a few sizes smaller,or go to dealer and see if he has a few to buy or try