1984 Mercruiser 305 with Thunderbolt ignition dies radomly.

[Gearhard]

I have a motor that dies randomly, at various times and RPMs. It's like someone turned the key off, no sputtering or other symptoms. It starts right up immediately afterwards. I suspect that it may be the sensor in the distributor and have a spare that I can install. The biggest setback that I'm having is the distributor cap retaining screws seem to be corroded and frozen so badly they may never come out. Does anyone have suggestions or a technique for removing these 4 screws or am I likely going to have to replace the distributor? Thanks for any help.

 

[achris]

First thing I'd do is drill the heads off them so you can get the cap off. Once the cap is off you should have enough of the screw left to remove them with pliers. I'd replace them with stainless steel..

 

[Gearhard]

First thing I'd do is drill the heads off them so you can get the cap off. Once the cap is off you should have enough of the screw left to remove them with pliers. I'd replace them with stainless steel..

Thanks, I tried that on a spare distributor and got the cap off, but when I tried to loosen the screws two of them broke off at the edge of the distributor. I was hoping to hear of a different approach that someone found successful.

 

[flashback]

A bit of penetrating oil may help once the cap is off and you can get to the shank.

 

[Gearhard]

A bit of penetrating oil may help once the cap is off and you can get to the shank.

thanks, but i even tried a lot of penetrating oil without any luck.

 

[alldodge]

Agree with drill but take the distributor to the bench.
Grind the stud flat even, then center punch it. Drill the screw out and if need be, go one size larger and retap. Can change the dizzy cap screws to one size larger if needed