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318 loses idle and stalls

D

Dennis B.

Guest
"LM318 runs good at idle leavi

"LM318 runs good at idle leaving the dock, approx. 15mins. thru speed zone. Runs up on plane (20 min.) at cruise (3000rpm). Problem starts when I return to speed zone and at dock. Won't hold idle in gear. I have just replaced the Dist. with a magnetic pick up, ECU,ballast resistor,voltage regulator. Timing is spot on (8deg.BTDC at idle, 26deg. advance). Just replaced the fuel/water filter and the in line filter tonight but still has problems.Seems to be fuel related, I have a Flowscan meter and it reads low flow. Cracked the fuel line at carb. and had good flow. Going to try the stone filter in carb. next. Almost seems like vapor lock, any ideas.I am just one wrench away from calling a mechanic."
 
"If it can idle in neutral or

"If it can idle in neutral or you can re-start the engine immediately after it stalls, it likely isn't vapor lock. How about the coil? Coils can do strange things when they start to break down. Spark plugs good? Gaps OK? Correct plugs for the motor? Plug wires in good shape?

If the problem is fuel related you might have a vacuum leak at the carb gasket. Idle speeds are where air leaks seem to show up."
 
"Jim, spark plug wires are new

"Jim, spark plug wires are new and plugs only have about 40 hours on them.Coil was replaced about the same time. Running a Q-Jet carb., and Floscan meter shows flow is low. Even revving the motor in nuetral will not increase the flow rate when this occurs. Going to try carb. replacement next, fuel pump replaced last season."
 
"When I had that same idle pro

"When I had that same idle problem, a new 600 CFM Edelbrock did the trick. I went through all the other attempted fixes first though before spending $350 for the carb..."
 
"Jim, where did you find a car

"Jim, where did you find a carb for that price?
I am also considering a new carb, no problems with ethenal gas and your new carb?"
 
"I'll see if I still have

"I'll see if I still have the shipping papers for the Edelbrock. No ethenol problems and I don't expect any. Edelbrock is definately on top of the game and have ensured all components are impervious to E10. Meantime, before springing for a new carb maybe see if you can find a known good compatible carb you can borrow & test on your engine. That'll tell the story.

Looking on the bright side, the parts you've replaced were a sound investment even if they didn't solve the puzzle; fresh parts on an engine make for some peace of mind..."
 
"Hey guys, just to let you kno

"Hey guys, just to let you know I replaced the carb (Q-Jet) with a holley marine carb I had. Runs like a top now! Will be investing in a Edlebrock 600cfm carb as the holley is a 750cfm"
 
Jeff wins the shopping prize..

Jeff wins the shopping prize...

Who'd a thunk it.
Amazon.

Congrats on the solution Dennis!
 
Warning! A Q-Jet and the Holl

Warning! A Q-Jet and the Holley replacement for it (a spread bore) uses a radically different bore spacing and bolt pattern from an Edelbrock 1409.

Translation? It won't fit.

Jeff
 
"They do, but it's a crapp

"They do, but it's a crappy deal (bad flow). Better to stick with something designed for it

Jeff"
 
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