Engine problem - '85 Mercruiser 170

[scook]

1) Finally got back to working on the boat. Pulled the sending unit and the tank is "like new" clean on the inside - I can't imagine there's any clog in the pickup tube with it looking that good. Any reason to think I should pull the pickup tube to inspect it? I suppose I could take off the fuel line and blow back through it to be sure???

2) Putting the sending unit back on, what gasket sealer (I'll buy or make a new gasket) should I use? We have some Permatex #2 and some Mil. Spec RTV.

3) Next thing to check. The only thing that changed from before to after the engine running for a while and then quitting is that I installed Pertronix electronic ignition. Talking with my son the mechanic, he said it sounds like a temperature related issue and suggested checking the ignition by firing it up and warming the distributor with a heat gun to see if that will make it quit.

Any more suggestions are appreciated - fishing season is coming up fast and I'm starting to paw the ground.