79 165hp 6cyl dying when warm

[Menace2Authority]

Let me start by saying I'm not in danger and a nice fellow has offered me his dock and a ride home. But when my 79 165 hp warms up it dies. Not overheating. Got fuel in the lines. When I turn the key its firing briefly. A sputter. So I have spark. But I'd rather not have to come back tomorrow to fix this thing at someone elses dock. Any ideas as to what might be the problem? Runs great till it warms up. First time it died at 180 degrees. Let it cool down, then it fired up and died at 140 degrees. When it dies it feels as though its running out of gas with a couple caughs before dying.

Thanks
Rob

 

[Menace2Authority]

Re: 79 165hp 6cyl dying when warm

I'm thinking maybe coil as playing with choke didn't help

 

[vxtech]

Re: 79 165hp 6cyl dying when warm

check battery & charging system , running battery down will give weak spark, make sure you have 12 volts at coil

 

[Menace2Authority]

Re: 79 165hp 6cyl dying when warm

A few beers in and I'm thinking the end of the planet here. I haven't checked compression but could low compression cause these symptoms? Reason I'm asking is purely because I do still have SOME spark as the motor does sputter. I have no experience with dealing with coil problems so I'm just kinda flustered at the moment I guess.

 

[lonemust]

Re: 79 165hp 6cyl dying when warm

A weak Very weak coil WILL give you a spark just not nearly as strong as it should be. Replace the coil, yours is breaking down. With the key on you should have a min of 4 volts no higher then 9. The only time you should have a full 12 volts is when cranking. Unless your engine uses a coil with a built in ballastor then and only then would you find full time 12 volts.

 

[John3]

Re: 79 165hp 6cyl dying when warm

Yep, try replacing the coil. I had a similar problem, ran fine until it got nice & warm then it died, waited a while till it cooled off, ran fine again till it got warm. Was the coil

 

[Menace2Authority]

Re: 79 165hp 6cyl dying when warm

Changed the coil. Seems to be alright now but I still haven't gotten it real good and warm. Will test it later when my buddy gets here with his boat in case I need a tow.
Rob

 

[Menace2Authority]

Re: 79 165hp 6cyl dying when warm

Boat still dies. I can run it to death at the dock in neutral with no problems. In forward it dies after a few minutes. Compression is 125 strsight across the board (give or take a pound or two of course). I'm really stumped now and ANY advice is appreciated.

Rob

 

[Fishermark]

Re: 79 165hp 6cyl dying when warm

You may have a fuel vent clogged. Try running it without the gas cap on and see if that helps.

 

[JustJason]

Re: 79 165hp 6cyl dying when warm

Sputters a minute doesn't mean you have spark.

You troubleshoot in this order.

1. Mechanicals
2. Ignition (and Charging if EFI)
3. Fuel systems.

You ruled out compression, which you state is 125psi and fine.

Since your not EFI, you need to go through your ignition system. You have points if not converted to something else.
Points, capacitor, cap, rotor, and plugs are yearly maintentece items. Have you done yours or not this year? Plug wires are good for 3 to 5 years depending on hours and salt exposure.

If you rule out ignition system, then it's time move on to fuel. I do this for a living and I would do a boat side fuel system test first, as outlinted up in the "adults only section" of the forums.
If the fuels system test passes, the you have a boogered up carb.