My Tractor Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
I have had ongoing problems with a B&S Vanguard engines.


It starts fine and runs OK until it is under the slightest load then it loses power every 20 seconds or so. At the point it loses power there is a brief puff of black smoke from the exhaust.

Valves clearances have been checked, carb stripped off and cleaned as thoroughly as I could. Air filter and oil changed. BTW the engine has done 200 hours

Spark seems OK.

I have noticed that there is some oil in the filter housing that is coming from the breather area (this was very clean oil).

I have not checked compression yet but am suspecting head gasket (hopefully not rings)

I also wondered if the flywheel key was slightly sheared putting the timing out. The engine is loose so it should be easy to check, do i need to remove the flywheel?

Also i dropped the float needle valve and bought a new one, why are there 2 in the packet (1 a steel colour the other brass colour) I used the brass one is that correct, they are slightly diferent lengths.


Any thoughts?
 

·
Banned
Joined
·
2 Posts
it could be the head gasket ...To check the fly wheel key on a brigs is undo the big nut and remove the hard ware you will see the key it should be lined up perfectly ....dose it pop threw the carb or back fire
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #3 ·
thanks

No it does not pop, it does appears to sometimes (maybe 1 in 3) backfire but only when it is switched off. Or at least there is sometimes a fairly loud bang.

By the way the breather tube that goes into the air filter housing does not appear to have any oil at all in it or on the surfaces.
 

·
Registered
Joined
·
19 Posts
I'd suspect after a backfire event that on one more of the push rods might be bent or out of the lifter all together. Look closely at the rockers to for cracks, I've seen it a lot in singles and twins with aluminum pushrods. Also, I'd would check the fuel solenoid in the bottom of the carb if equipped, if dirty or acting up (wiring) it will allow for the backfire to occur.
 

·
Registered
Joined
·
87 Posts
if its a puff of black smoke thats fuel ,pull the carb take it apart and clean everything install a new fuel filter and maybe some dry gas in the tank
Greg
 

·
Registered
Joined
·
19 Posts
You might also just be your own worst enemy:Stop:
If it didn't have the brass needle originally different lengths do make a difference, the carb may be just flooding. I'm just sayin'.
 

·
4K Poster!!!
Joined
·
4,504 Posts
Black smoke means it's running rich. You need to check your float level. Perhaps you put the wrong needle in, and the fuel level is too high in the bowl.
Is there a main mixture adjustment? Perhaps you just need to lean it out a bit.
 
1 - 7 of 7 Posts
Top