bobcat 610

[guss]

bobcat 610 with a vh4d engine
starts right up, but back fires thru the air cleaner
changed plugs and wires
changed fuel pump and filter

 

[Fabricator]

Backfire makes me think advanced timing - i.e.: intake valve is still open when the spark fires.

I'd put a timing light on it to start there.

 

[guss]

from what i found on the net, the firing order doesn't seem right
it looks like they were on output shaft side of the engine instead of by the fly wheel when they put the wires to the plugs.
would the engine even run like that?
this is throwing me off

 

[guss]

it looks like 1 and 3 and 2 and 4 are switched

 

[foton]

different manf. set how they count the cylinders differently , there is a few things you need to know what end of the engine do you start from, is it left to right or right to left or back to front or whatever and the firing order and the rotation of the dist. and then set a tdc at that point it should go. check the block number to verify your info. sometimes things get changed from one series of engines to another.

 

[guss]

the wires seem right, won't run if i change them.
they put an electric fuel pump on but i couldn't see any numbers on it.
i put a new one on, 2to 3.5 psi.
it runs much better.
goes ok forward and backward, but the engine wants to die when turning
and i can't find anything about where the settings should be on the carb

 

[Fabricator]

Mismatched firing order would definitely cause issues. If you're confident you have the right order, have you checked the timing?