V twin not running well

[Bulthy1]

Hi Everybody,
I have a old briggs & stratton v twin that only fires on one cylinder,
have a good spark on both plugs, I swapped the coils over & plugs.
cleaned the Kiki carb in ultrasonic bath .
set the valve clearance to 5 tho on both intake & exhaust.
Sometimes it will run with both cylinders firing but only for a few seconds.
I have very little hair left to pull out, Help
John

 

[MowLife]

What model Briggs do you have? Hope you mean .005 with the valve clearance.

 

[Rivets]

I suspect you have a blown head gasket on the cylinder you think is bad. How are you testing to determine it is only running on one cylinder? Is there spark even after you suspect the cylinder is no longer operating correctly?

 

[Bulthy1]

Hi Everybody,
I have a old briggs & stratton v twin that only fires on one cylinder,
have a good spark on both plugs, I swapped the coils over & plugs.
cleaned the Kiki carb in ultrasonic bath .
set the valve clearance to 5 tho on both intake & exhaust.
Sometimes it will run with both cylinders firing but only for a few seconds.
I have very little hair left to pull out, Help
John

Yes I meant .005, the engine numbers are 351777 1124-E1 98020511

It runs OK on left hand cylinder right hand will fire randomly, I have replaced the head gasket, push rods are OK
I don't have a compression gauge but it will push your finger from plug hole quite well.
John

 

[MowLife]

I am thinking about your carb. Some carbs are 2 barrel with one barrel feeding each cylinder. If you have this type carb it is very possible 1 side is not running correctly and would show the symptoms your having.

 

[bertsmobile1]

Time to stop, look , listen & feel.
Remove the rocker covers and rotate the engine slowly in the correct direction by using palm pressure on the finger guard/ debris shield.
Listen to the gasses feel the resistance & watch the movements of the rockers.
The amount of resistance before TDC should be the same for the left & right cylinders, the sucking & whooshing of the charge should be the same and each valve should move in & out the same amount.
When fully out the valves should sit at the same distance off the rocker housing floor.
Spend some time and tell us what you noticed.

 

[Boudreaux In Eunice La.]

I have seen your issue before.......... The side that is running rough more than likely has a bad coil...... It is going out..

Only way to check is to put 2 inline spark testers and run it..... Look at the testers for the bad one since you have swapped them out...........

Let us know Mon Ami ~!~!