Ignition problems

[Ruprecht]

1979 260 mercruiser Chevy 350 block:
We were having problems when we were running the boat for a while and then it would stall and not start back up or fire sputter and die. Started right up and ran smooth until hot. Marina mataince guy suggested checking how hot the coil got, ran till stalled and could barely touch the coil for a few seconds. Was told resistor could be bad and to replace coil with a coil w/ internal resistor since couldn't find the inline resistor. Well rushing to get it done before work and hooked the black wire going to the side of the distributor to the positive side instead of negative. Tried to start boat and blew breaker and 90 amp fuse on the starter cylinoid. RePlaced fuse, points, condenser. No start. Getting 12v on power line to coil 7v coining out of coil to distributor. Ignition on, move points by hand, no spark at points. Not much spark coming out of coil if any when tower wire is grownded to engine block. It used to always start right up before mishap... Don't know what to do next... Oh, pulled tack wire in case of short... Among other things...

 

[Don S]

Re: Ignition problems

Put in a new set of points and condenser (it's called a tuneup) spark plugs, cap and rotor. Set the dwell, then the timing.

Changing coil types was a stupid suggestion. Wasn't fixing anything, just trying to cover up the problem.

 

[Ruprecht]

Re: Ignition problems

Put in a new set of points and condenser (it's called a tuneup) spark plugs, cap and rotor. Set the dwell, then the timing.

Changing coil types was a stupid suggestion. Wasn't fixing anything, just trying to cover up the problem.

Already "tuned up". As I stated we put in new points and condenser...tested coil and get a spark. When we put the negative wire from the side of the distributor back on the coil we lose all spark even when we manuelly open and close points. Any other suggestions?

 

[Don S]

Re: Ignition problems

See if you have the black wire going to the wrong spot on the points. You could be shorting the coil to ground.

 

[Reel Poor]

Re: Ignition problems

Also be sure the ground wire inside the distibutor is connected to the pionts mounting screw. The points contact surface may need to be lightly scuffed with a point file or sand paper (fairly common issue with new points).

 

[Ruprecht]

Re: Ignition problems

See if you have the black wire going to the wrong spot on the points. You could be shorting the coil to ground.

It shorts out when we hook it to the bolt that comes out of the distributor where the points and condenser hook on the inside. So either the points or condenser must be grounding out somewhere.

 

[Reel Poor]

Re: Ignition problems

It shorts out when we hook it to the bolt that comes out of the distributor where the points and condenser hook on the inside. So either the points or condenser must be grounding out somewhere.

If the points are closed it is a short to ground, that's how it works. Place a paper match or similar between the point contacts to see if the shot disappears. If it does things are working properly there.