Ran for a few seconds then shut down

[pdecker]

After years of flawless service from my A-4, I tried to start it after anchoring out overnight. It ran for a few seconds and quit. I cranked it again a few times, and it ran a shorter period of time and then quit.

After getting towed 15 miles back to the marina, I replaced the Racor 10 mic filter element, which was dirty, and replaced the electronic fuel pump, adding the in-line filter kit from MMI. Now it will only run after spraying the carb with starting fluid, then it quits. I took the new hose off the carb and noted it was completely dry after cranking it for 30 seconds or so, meaning it's still starved for fuel. I also verified the fuse from the oil pressure switch, to which the fuel pump is connected, was still good.

I noted that when I crank the engine, I only get 8 - 10 PSI of oil pressure on the guage. I recall that the engine runs at 20 psi oil pressure, with little variation whether cold or hot. Could the problem be the oil pressure switch, which is supposed to cut out at 6 PSI +/- 2? I also tried to adjust the oil pressure adjustment screw, but could not budge it with the tools at hand.

If it's not low oil pressure, could the symptoms be caused by a clogged carb jet? I don't want to dig into the carb if I don't have to.

Phil
S/V Catmandu
1982 Catalina 27

[sastanley]

Phil,

If it has been years since you've cleaned the carb, it is probably time to do so. However, it is easy to do too many things at once and then you never know which thing fixed the problem. You've introduced more possible scenarios with the new pump too.

First, we need to get fuel to the carb..then if the carb is also dirty, we can clean it later.

8-10 cranking PSI should be enough to trip the OPSS.

Take a jumper lead and bypass the OPSS to make sure the fuel pump is getting 12v. If the jumper works & the fuel pump runs and the engine starts, your OPSS or part of that circuit is suspect. If it won't start, confirm you are getting fuel to the carb, and we'll take the next step of removing the carb for a cleaning.

As a seasoned A-4 vet, I am sure you are closing the raw water intake if you are cranking for extended periods, right??

[pdecker]

another piece of data

Thanks, and yes I remembered to close the through-hull. I know about hydro-lock. Been there, done that, bought the t-shirt.

Just before the engine quit the first time, I had quickly switched the batteries from the starting battery to the house battery (through the ALL setting, not the NONE setting) since I wanted to recharge the house battery with the alternator. The engine quit shortly after that. I thought I might have caused a power surge that knocked out the fuel pump by switching the batts too quickly, and that's why I replaced the fuel pump first.

Also, I haven't cleaned the carb in ten years. I'll take your advice and jumper the OPSS, and then see if the carb is getting anything if it doesn't start.

Phil

[Mo]

Easy things first. Check that fuel in tank, double check that no gas-line valves closed, check fire, fuel shut off switch. Then take carb apart taking care to preserve the gaskets. Remove jets and use a welding tip cleaning tool (looks like a feeler gauge but various rounded probes...excellent for cleaning out jets) to clean the jets. Use carb cleaner or brake clean to spray down the whole carb and blow everything out with compressed air if you have it.

This sounds like a gas issue like stated, however, if no change there, check fire. If you have points and condenser don't overlook it as a contributor.

[roadnsky]

...I replaced the Racor 10 mic filter element, which was dirty, and replaced the electronic fuel pump, adding the in-line filter kit from MMI.

Phil-
What Electric Fuel Pump do you have?
Is it the FACET?

[JOHN COOKSON]

It ran for a few seconds and quit. I cranked it again a few times, and it ran a shorter period of time and then quit.

I noted that when I crank the engine, I only get 8 - 10 PSI of oil pressure on the guage. I recall that the engine runs at 20 psi oil pressure, with little variation whether cold or hot. 1982 Catalina 27

+1 on what Shawn said. A defective OPSS will give these symptoms.

Do you have a wire from the starter that bypasses the OPSS so the fuel pump operates when you crank the engine before the oil pressure rises?

BTW oil pressure S\B ~ 40 PSI at cruise RPM when the engine is warmed up.

TRUE GRIT

[pdecker]

Solved: it was the oil pressure safety switch (OPSS)

I went in to jumper out the OPSS, and had to use a mirror and a flashlight to see the second terminal on it. The second terminal was extremely corroded! I made a jumper cable with alligator clips and wire, and dug the clip into the terminal through the corrosion. The engine started fine and kept on running.

So, I ordered a new OPSS from Moyer Marine, and installed it today. I made sure to put dielectric grease on the terminals to prevent corrosion. The engine runs great!

Now that I have the old switch out, I still cannot get the old screw out of the terminal because of the severe corrosion. I finally figured out how to test the ten year old Facet electric fuel pump I took out, and found it that it runs. I'm keeping it onboard for a spare just in case.

Phil
S/V Catmandu
1982 Catalina 27

[Beckeresq]

Along the Same Line

For the past six months I've been trying to start a "gift" engine that I got in parts and which had not run in 12 years. Fun project-not a professional rebuild, but let see if I can put it together and start it.

It now starts and runs a couple of seconds and stops.

This thread gave me another thing to try--dress up the seat on the OPSS.

Oops, no ball in the threaded hole, just the spring. Ken doesn't sell the ball-Moyer Marine has gone to a better switch, but I just want to see if the engine will run.

I think the ball is 3/8" diameter and have a question in to Don.

Can anyone confirm the size of this ball? Any suggestions on where to get one? My Son will kill me if he sees me taking apart his skateboard wheels.

[JOHN COOKSON]

Did you try starting the engine with the spring out to see if the oil pressure will blow the ball out? You'll have to catch the oil in a rag or something so it doesn't make to big of a mess.

OPSS=oil pressure safety switch. Coast Guard required with electric fuel pumps so the pump won't pump fuel when the engine isn't running. It's activated by oil pressure. If you think it is defective temporally short across or bypass it and see if the engine runs for more than a few seconds.

Did somebody put the OPSS in the oil pressure adjusting port? It should have it's own port. I always fill the cavity in the OPSS with oil before I install it to be sure there is no trapped air.

TRUE GRIT

[Beckeresq]

The ball isn't stuck, it's not there. Someone probably took it out while the engine sat idle and in pieces.
The local NAPA Machine Shop just sold me two balls from their extra parts jar to try. That did it. Now have oil pressure, and engine ran for at least a minute and one half--on to fuel problems.