1975 302 188hp merc stalling problems

Hey there. I'm a new boater this year. I purchased a 1975 cuddy with 302 merc 2barrel carb. It sat for the last 2 years. I've drained gas tank and put new fuel and stabilizer in it and replaced fuel/water separator. Here's the prob, it runs great for about 10-15 mins then will stall without warning. Sometimes it will fire right back up and sometimes it takes a bit of messing with the throttle to make it go. But when it does restart, it only lasts for a few seconds. I've already replaced coil pack, and was not the prob. Next I'm pulling carb to rebuild and replacing point and condenser. If this does not work, is there anything else I can try. Any feed back would be appreciated. Thanks!

 

try replacing the ballast resistor. if its not that i would look for a fuel restriction or faulty fuel pump.

 

Ok thanks for the input. I will definately look at that if the problem still continues after the carb rebuild

 

depending what distributor you have in that engine, some had failing rotor buttons.
I remember replacing quiet a few
The ballast resistor is not a single unit on marine engines it is a wire in the loom, never seen a bad one?

 

my 318's have seperate ballast resistors under the ignition module covers and my 302 mercruiser had a seperate one as well. my engines are pretty old though.

 

Runs well for 15 minutes at what,--- cruising speed or idle?

Ballast resistor is for starting it will run without but the 10V coil will run on 12 V and will burn out eventually.

 

Common shady tree mod to a Mercruiser was to install a automotive ballast resister (with new coil) to the end of the ballast wire ( the only key on power at the engine) because they didnt understand what they were doing now you have 2 ballasts inline..DOH

 

i have had bad resistors in cars which run for a few minutes then cut out because they would over heat and cause to much resistance due to being stuffed. whether it is a seperate resistor like my chryslers have as standard or a resistor in the loom it can happen. i am not saying it is the problem just that it could be. maybe he has crap built up in the pump and fuel lines from sitting around. now you 2 can go on about how you have never heard of dirty fuel or clogged lines as well.

 

No I have heard of fuel blockages and I agree that would be a better way to go.

However im not that good at diagnosis that I can say whats gone wrong when I don't even know it if stops when it runs for 15 minutes cold? at idle? or at 3000 rpm.

Perhaps we should wait for this information before we go any further down the long list.

 

exactly

 

i wasn't trying to diagnose his problem, just threw in a couple of suggestions for him to try but once again i have been shot down in flames.

 

I had stalling prob with mid 70's 302 just before it caught on fire. Fire was caused by faulty fuel pump dumping gasoline onto outside of engine. Diaphram cracked.

 

It did that with a genuine pump??

 

Yep. I was driving a Crown Vic on I-275 at Malfunction Junction. It lost power as I drifted onto the left shoulder. I parked it and watched it burn while I waited for the Fire Dept. I pulled the hood release but it was some kind of nylon cable which had already parted from the heat.

 

ok so not a boat engine
they have different pumps to prevent that happening