Ok, I've been having troubles with this mikuni but its pretty much come down to this..

After making a run wether it is half a mile or 10 miles the engine will not start after I turn it off at the end of the run. I must wait at least 15min for it to cool down before it will even try to start. Right when I cut it off I notice gas dripping from the overflow hose from the mikuni.

Is this just a matter of bending the float tab or is something else causing the starting problems?

thanks

pd 36 w/single mikuni

Do you have an electric fuel pump? Def sounds like its flooding. If you have a pump, make sure it's turning off when you cut the motor. If you don't check the float and go from there.

No electric pump.

Will bending the tab on the float fix this or is it caused by something else?

The diaphragm could have busted on your stock pump, but I'd check your float first. I don't know what else would cause it. Def sounds like flooding. Check your pick up tubes for clogs also...maybe?

Ok, well i'm gonna try to get the bottom of the carb off today, tried before but the screws were tight as hell. Putting some penetrating oil on before I go back to work.

Is there any way to determine if the stock pump is busted other than getting a new one?

Also, when I start it sometimes backfires through the carb a couple times when its cold.

I'm def no carb expert (or mine would be right), but all those symptoms sound like float needs adjustment or its sticking. Check there first. It could still be the pump. I don't know how to test it other than to take it apart. There's not much to it. They are not expensive to replace though if your carb checks out.

to check ur pump take off the fuel line that goes to the carb and turn the engine over and if it spitin fuel ur pump is good!!! The problem u are havin dosen't sound like the fuel pump cause u wouldn't go far with a bad fuel pump u might beable to get on step and that would be it!!!

Do you have an oil pressure sensor? (side of the motor near the oil filter). If so, try disconnecting it and see if it starts, those solenoids can go bad and if it trips, it will not start.

i'll check for the sensor tomorrow.

Didnt get time today to get the carb apart, hopefully tomorrow.

Been thinkin about it since db8 posted, but why would the carb be leaking fuel if it was just the sensor? I could see why that would possibly keep it from starting, but the fuel dumping outta the carb still makes me think its just flooding...

The fuel from the overflow, is just that, overflow. The float tab needs to be adjusted. That's not gonna fix the warm start problem, tho. I'm guessing that's why DB said to try disconnecting the oil pressure sensor. They are a common issue with Briggs.

Thanks camo.

No sensor that I can see. Only wires on the oil filter side of the motor are for the tach.

I adjusted the float and there is no more gas coming out of the overflow.

It still wont start when it's hot. I can keep trying to start it but it just backfires out the muffler.

Any more ideas?

I sprayed carb cleaner in all the holes when I had the bowl off.

Not sure if it's in the same place on a vertical motor or not, but on a horizontal the sensor is in the block, just to the rear of the oil filter & will hav a single wire with a blade fitting on it. The wire runs across the front of the motor (inside the front cowling), just above the coils, zip tied to the intake, & into the wiring harness. Once ya find it (it's on there somewhere - has to be), just unplug it & see how she does.

Most of the marine CDI models don't have them. It was a thought.

When you crank the motor when its not starting, do you see RPM registering on the tach? (if its getting spark you will see it register). Its either air, fuel, or spark.

Also, have you checked your valve lash?

Not a cdi motor, I'll look closer for a sensor tonight.

Another thing, it will not run at idle with the prop engaged in the water, it's like it bogs down and dies.

it sounds like the rev box is getting hot and shorting out to me try unplugging it and see if that helps. but ya the overflow is the float in the carb needed to be adjusted

Well I just checked and it is showing rpm on the tach when I try to start it so I would say that rules out electical...is this correct, plus it only idles at 1300rpm or more so I would think it has to be motor or carb.

Valve lash..everything is stock other than muffle and carb, could it have changed with nobody meaning with it?

Keep the ideas coming, I really appreciate it!!! This thing is driving me nuts

Just read that this motor should idle at 1000-1100. It wont idle at anything under 1300 without dying right away.

Intake leak? Try spraying carb cleaner all around the intake with the motor running. If it bogs down, ya got a leak.

Valve lash also possible. Even though the motor hasn't been internally modded, the valve adjustment can still be off.

Ain't this the same motor that was doin this before the carb was added?

I'll try checking for intake leaks again, did it before with no results.

I've set the valve lash on a sbc that was on my airboat but never a small engine, what should it be set at?

Yes, this motor had idle problems before the carb was put on but not the problem with it not starting.

.004-.006 is the tolerance for valve lash. Set both intake and exhaust at the same time. 1/4 past TDC on the compression stroke. Then move to the other cylinder and repeat.

Valves adjusted to spec..the intakes were too loose and exhaust was way tight.

Motor runs like a champ now!!! Starts, idles in gear, everything!

Thank y'all so much for the help, on the lake now beer in hand and a hook in the water

The bill's in the mail.