Logo
FULL SITE MENU

Carb fire

S

stevenelson

New member
" Sparky, thanks for helping.

" Sparky, thanks for helping. Could you tell me if it makes a difference which vaccum hose goes to which intake manifold nipple? They gave me 2 vaccum hoses with the carb set. One has 2 outlets, one has 4. Background: The motor{89 200hp Johnson Looper} flooded when I had the motor tilted up quite a ways while we were idling out during a low tide. When flushing, I found gas leaking, and subsequently found 3 carbs, vaccum hoses and inside of silencer box all partially melted. I did not here a backfire,nor did we see any smoke other than when initially starting after flooding. Any ideas as to the underlying cause? The heads do not show any signs of overheating. How could 3 carbs melt without even knowing there was a fire? I am switching to 225 carbs. The timing appears to be the same for both engines. Do any changes need to be made? Thanks again for any advice. "
 
"Steve.... This may be of some

"Steve.... This may be of some help.



Joe
"
 
" This is exactly what I need

" This is exactly what I need Joe. I really appreciate the help. Do you think there were underlying problems, or just a fluke due to the motor being tilted too high and flooding? Even after the fire the motor started easily and did not noticably run poorly. "
 
"Steve.... With the engine in

"Steve.... With the engine in a level running position, pump the fuel primer bulb up hard. If fuel flows out of any carburetor throats, obviously it/they will require reworking.

Since the carburetors will in all likelyhood be off, even if none of them flood, it might be worth wile to check the float levels as follows.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

Another thing.... I've seen many a carburetor flood bad but have never seen that condition cause a fire by itself. I would suspect either a faulty reed plate (leaf valve) that would allow a flame or super heated air to be forced to where the fuel was.... or a external sparking condition on the engine somewhere that may have ignited that fuel.

Running the engine in the dark with the hood removed, on a flushette would reveal any sparking condition. Good Luck.

Joe
"
 
"Joe, I had the intake manifol

"Joe, I had the intake manifolds off, had them checked, and replaced the gaskets. I rebuilt the carbs and finished connecting the hoses. Checked for leaks and fixed a couple, but primer ball never really gets hard. I dont see any leaks and have changed the ball 3 times. I started the motor, and it was running worse than with the melted carbs. It was running at a very high idle, about 1500 or better, and it was backfiring on more than 1 cylenders initially, shut it off checked everything, restarted, still high idle, and backfiring on 1 cyl for sure. I had not changed any adjustments. It was dusk and I did see some sparking by carbs when backfiring. If I got the vaccum lines switched at the solonoid, or a gas line wrong would it cause this? Thanks for all the help."
 
"Steve.... Not being there, it

"Steve.... Not being there, it's pretty well impossible for me to pinpoint the problem. However, if you've had the flywheel off (nut torque 145 foot lbs) and didn't torque it properly, it's possible that the key has sheared slightly which would throw the engine out of time somewhat. Usually if a key shears, the engine doesn't run at all but there are exceptions.

If one of the carb butterflies are slightly open, that will allow the engine to spit back which soulds like a mild backfire. Those butterflies must all be unform whereas all open and close at the same time.

Another thing might be that you have the jets installed wrong (it happens)... check your manual, and make sure that the seal rings on the back of those plastic carbs are seated properly. Get one pinched, cut, out of line, the engine will run lousy.

Joe
"
 
" Joe...I got it all back toge

" Joe...I got it all back together, took it in to have it synk and linked. He told me it may run a bit rich, and it did. About 5000 rpm max, and 35 mph. This is with the 225 carbs on it. With the 200 carbs pre fire, I was getting 54-5600 rpms and 40 mph. Is this an adjustment I can do myself?, or should I just take it back in. Im into it with way too much money to stop now. Again, the generic manual doesnt tell me specificly how to lean the motor out. Also, I'm mixing gas not using vro. Thanks again for the help. Your advise is very sound.


Steve "
 
Back
Top