Originally Posted by Searles
Check the fuel tank
breather ,must be clear and rising all the way,,also maybe a intermittent air leak in the fuel lift pump, try an electric
on line pump before filters and lift pump ,but it really sounds like a sticky governor ..please post all test results ,most interested ⛵️⚓️
Distinct possibility. Open the fill cap and it should resolve issue within a minute or so. Or alternately loosen cap and see if the problem comes back at all.
Assume you tightened the pump to specs and equally? just to toss out a few ideas.....Not syaing I'm right or wrong just offering possibilities of what may be. It's either a not enough fuel or blocked exhaust. Blocked exhaust should not come and go unless it's a ball sized chunk of junk. Like a broken catalytic converter in a car/truck. Highly unlikely in a boat. So fuel side of the mechanical and fuel makes it go equation.
You might also check for exhaust back pressure either by eye balling the elbow
or taking the salt
hose off and putting a pressure gauge on it. Should be less than 2 psi back pressure. It should not come and go like your symptoms though. Improbable but possible.
Governor getting stuck is very possible but rule
out everything else.
When it happens try smearing thick grease on any of the inlet fuel line fittings to try and rule
out vacuum leak. This incudes line into the lift pump, in and out of the filter and inlet at Injection Pump. Clean off later with a rag/cloth and brake/parts cleaner. If you have a smoke generator
that's another way to test for leaks
. Or air pressure and soapy water
. Apply air pressure (2 to 5psi) at inlet line from tank and check the line all the way to the injection pump. You'll have to purge the fuel from the lines first though for either air pressure or smoke generator
You might try advancing the pump about 5* and see if it helps. Or retiming it all together but if memory serves you need some tools a DIYer probably won't have. You might be able to rent or borrow needed tools from the rebuilder if he has them.
You have checked the pickup in the tank just for sh*ts and giggles but running on a separate tank without joy should rule the pick up being intermittently clogged. I had one car years back that drove me nuts and ultimately turned out to be the foil cap off a fuel treatment bottle the owner had mistakenly put into tank. Would randomly run fine until it didn't. Shut off the car and it would run fine for a week or an hour. This was before screens on pickup tubes. Weird problems sometimes have weird solutions.
From your descriptions I would bet a small amount that there is an issue with the rebuild
in the governor assembly. Can we assume there was no issue other than fuel leaking out of the top of the pump prior to rebuilding it? As in no running issues as described before you removed the HP/Injection pump? After pushing a wrench over 50 years the first place we usually look for a weird problem is who just did what to it, just to rule it out. This includes the washers and the fittings, pump timing, etc. etc. If the issue wasn't there before the pump came out but is there after the pump went back in, I'd look at both the install and the rebuild
. I would not rely on marks made to time it.