Challenger 2000 with the Mercury 240 EFI backfiring, won’t start.

[lyttlea]

Hi Guys,

Wonder if you can help.

It sounds like there is too much compression. I have a spark, Fuel and have had the timing light out and set the base timing to 8 degrees. It has backfired a few times while trying to start it but in most attempts it only turns over for a second or two before the compression is too great and it stops.

I have been trying to fix the problem with all the adjustments on the throttle arm but no luck


Hope someone can shed some light.

Thanks

 

[Dr Honda]

The only way it can have "Too much" compression is if the cyl's are full of fluid, or there is a serious mechanical issue. BUT... on the merc engine, fluid in the cyl's is almost impossible since the engine is mounted on its side. (it will go out the exhaust)

BUT... to make sure... take out the spark plugs, and give it a crank. If there's liquid in there... it will come out.

To me... it sounds like:

1) Battery is weak.

2) You timed the wrong cyl.

3) The trigger unit is busted.

4) The ignition wires got swapped somehow.

5) The throttle guardian is dead. (if it's even still there)

 

[lyttlea]

Hi Tony,

I think it was the battery, I was getting 12v at cranking but it wasn’t immediate, the voltmeter took its time to get up to 12v. I took the starter solenoid off cleaned all the connections but nothing changed, so I stuck a jump lead from the starter to ground on the battery and it started turning it over properly,so I have an earthling problem! it got closer to starting, I think the timing is still off.

 

[lyttlea]

Hi. Any reason the timing won't change? I can't seem to get it timed it's still way off?
Any help would be great

 

[Dr Honda]

Timing that engine isn't straight forward. You need the manual and follow it step by step. Also... are you looking at the right cyl for #1 ?? (top starboard side)

 

[lyttlea]

Yeah we were looking at the correct one. It was looked at by a marine mechanic today. He spent 2 hours trying to figure it out. He also said he couldnt get it timed, no matter what he did. I have had it running twice but as it was out of water i shut it down quite quickley.

He is going to take the flywheel off and investigate, it has a new trigger so im very confused. If you have any idea please help me out

 

[Dr Honda]

Was the new trigger OEM?? Did you look at the plug (wire connections) and verify if they are in the right position?

Unfortunately... from this end of the keyboard... it will be hard to say what could be wrong.