5.7L Thunderbolt V Won't Start

[bigboogar]

My 5.7L Mercruiser has been running great all summer. Last weekend we went out, stopped in the lake and couldn't get it restarted. We towed it back to the dock. Next day went out. Started right up. Took it out about 500 yrds. It started to sputter and backfire, I got it back to the dock- barely - then it died and I haven't been able to start it since.

I replaced the fuel filter and coil, starting fluid in the carb doesn't help. I'm getting voltage to the "+" side of the coil but no spark.

Any suggestions ??

 

[mkast]

Re: 5.7L Thunderbolt V Won't Start

Don't use ether to start the engine.

 

[snoski]

Re: 5.7L Thunderbolt V Won't Start

No spark where? It is real easy to check the spark with a timing light. First start at the infeed wire to the distributor and connect the timing light there, spin the motor over, and see if it lights. If you have infeed power, then check all the leads to the spark plugs. If you have fire there, then you have a fuel delivery problem and not a spark problem.

 

[ryendube]

Re: 5.7L Thunderbolt V Won't Start

kjh

 

[bigboogar]

Re: 5.7L Thunderbolt V Won't Start

No spark where? It is real easy to check the spark with a timing light. First start at the infeed wire to the distributor and connect the timing light there, spin the motor over, and see if it lights. If you have infeed power, then check all the leads to the spark plugs. If you have fire there, then you have a fuel delivery problem and not a spark problem.

Do you mean to start with the wire from the coil to the distributor ?, then the plug wires ?

 

[gadget73]

Re: 5.7L Thunderbolt V Won't Start

Check the bullet connectors in the wires from the distributor to the ignition module. I had intermittant backfiring and random odd running with mine that I chased for nearly a month before it finally just stopped dead while cruising. I had no spark until I pulled those connectors apart and realized they were corroded. A bit of cleaning and its been running like a top ever since. The wires should be white/green and white/red. Some have ring terminals and studs on the back of the distributor. Either way, make sure the connections there are good. If the signal from the ignition pickup isn't getting to the module, you have no spark.

 

[Don S]

Re: 5.7L Thunderbolt V Won't Start

Don't guess, or start swapping parts, troubleshoot.