Engine problem - '85 Mercruiser 170

Could possibly be a sometimes clogged pickup in the fuel tank. Try running the boat from a portable tank for a while first, before you plunk down money on a pump. You may even be able to remove the pickup and see if it is screened at the bottom. Easy enough things to do before spending money.
 
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.
 
To recap the thread, this is after new fuel lines, fuel water separator filter, fuel pump and draining the tank and filling with non-ethanol gas. The 15 hp 4-stroke outboard runs off the same tank for long periods with no problem.
 
try a remote tank just to eliminate fuel supply as an issue. Take a volt meter with you, when it shuts down, check voltage at the + terminal on teh coil, it should be above 8 volts, if it won't start back up, run a jumper wire from the + terminal on teh coil to the + termoinal on teh bagttery, if it runs then, you're resistor wire(purple/white stripe) is breaking down. Cut the harness back till you can find a purple wire, splice a new purple wire intoit and repalce the purple/white with the new wire to the coil. Also, make sure the wires to the pertronix didn't get chafed when you installed it, make sure the black wires runs to the - terminal on the coil is good and secure. Is that a new coil? Two more things, disconect the tach wire at the coil(grey)and see if it runs better. If that doesn't help, disconect teh shift assist wire at the shift switch(white/green stripe). Becarefull if you disconect the shift switch, it will be difficult to get it to come out of gear. You may have to cut teh switch off to get it to shift. Stay out in open water doing this test(away from docks and other boats)

If that doens't get the job done or if youhave any questions, call me next time your on the boat, I'll walk you thru a few things. David Hall (843) 532-9148
 
Thanks David - I'll try all that stuff before bothering you. I really appreciate your generosity - you saved my sanity a few years ago when I was fixing the water pump and it looks like you may do it again.

Thanks again - Scott
 
Doesn't the PERTRONIX need a full 12 volts to work? I thought when you went to a PERTRONIX, it is reccomended to go to a matching coil and do away with the resistor.
 
been a while since Ive done one, but they used to require a minimum of 7 volts. I always bypassed the resistor regardless just to eliminate it causing issues. I haven't done one recently, but 12 volts is better than < 12 any day
 
I got their flame thrower coil with it and cut out the resister wire. I've got 12 V plus. I read Spare's suggestion that I should check it right when it pooped out to be sure something wasn't changing as a result of operating the engine - temperature or some other cause. Intuitively, I don't see what would cause the voltage to drop and if it did, would it cause RPMs to decrease as opposed to just dropping off suddenly,to zero. Of course, my intuition hasn't got the problem fixed either.
 
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