Engine Won't Start

[greg82255]

Hello,

I have a 1986 Mercruiser 260/Alpha One, thunderbolt IV ignition system. Ran the boat for 20 minutes this morning, it was running fine then started sputtering and stalling every few seconds. I could get it started and it would sputter and then quickly die. Then it wouldn't start at all, will crank all day but nothing. I thought it was a fuel problem, but I then checked the spark and there's now no spark. Any ideas what might be wrong? I was all ready to go boating today...

 

[45Auto]

Re: Engine Won't Start

Best thing to do is go down the checklist in the manual to troubleshoot the ignition. Could be the coil, distributor cap, rotor, coil wire, ignition sensor, control module, etc.

If you just want to try solving it by randomly throwing money at it, the original ignition sensor in that era had a habit of crapping out.

http://www.ebasicpower.com/pc/MAL9-29804/MER10C

I had to replace both of them in my twin engine '87 Alpha 260 Searay.

 

[greg82255]

Re: Engine Won't Start

so now it fires for a second and dies. It must have spark because its firing, but now I think it's a fuel problem because its dying almost immediately. Once it ran for 15 seconds and died, then it fired for a second and died. What to do now? I'll probably replace the water separator filter, but what after that?

 

[Don S]

Re: Engine Won't Start

Check for power at the coils + terminal with the key in the run position.

 

[greg82255]

Re: Engine Won't Start

Are there instructions online on how to do that?

 

[Don S]

Re: Engine Won't Start

Are there instructions online on how to do that?

Instructions for what?

 

[greg82255]

Re: Engine Won't Start

Checking for power at the coil and terminal

 

[Don S]

Re: Engine Won't Start

Turn the key to run. Use a volt meter (DVM) set to DC volts, put the red test lead of the meter on the + terminal of the coil, the black test lead on a good clean engine ground. Read the volts in the display of the meter.

 

[greg82255]

Re: Engine Won't Start

12V at the + terminal on the coil when the key is in the on position. I assume this means that power is getting to the coil? The coil is brand new. Where should I look next?

 

[Bondo]

Re: Engine Won't Start

Where should I look next?

Ayuh,... For a Mechanic,... Yer in Way over yer head...