fuel help needed, boat stalls for no reason

[gregsails]

Looking for suggestions. I rebuilt my entire motor. Rebuilt the mechanical fuel pump and the carb on my 1977 Catalina 30 as well.
Motor starts within 3 sec of turning the key and sounds smooth. Very happy with the rebuild.The issue is this.
The motor runs for 15 minutes and stalls out without any warning. Stalls very quickly, only 1 to 2 seconds and its gone, no warning.I turn the key, and it immediately starts up. If I run the motor at idiol speed with the boat in gear, it will run and not stall. Any more fuel than that and after a few minutes, but not right away, it will stall and then will be able to start right back up.
Not really sure what is out of whack. Any opinions as to where to start.And by the way, today I by- passed all the fuel filters and tank and used a 5 gal plastic tank and went direct to the carb to eliminate that part of it.Same old.
Thanks
Greg Catalina 30 1977

[Mo]

And by the way, today I by- passed all the fuel filters and tank and used a 5 gal plastic tank and went direct to the carb to eliminate that part of it. Same old.
Thanks
Greg Catalina 30 1977

Did you by-pass the pump and use a bulb pump or was your mechanical pump drawing the gas from the can? Does sound like an air leak and since you've been working there should stick it being a fuel issue first.

-check oil and see if you have a rise or clear thin oil...might even have a hint of gas smell to it.
-also remove cover and smell where you put oil in to see if there's gas smell.
-check line between pump and carb and ensure all fittings tight and not leaking.

I'm sure some guys with some other ideas will chime in as well. This could easily be an electrical / ignition issue as well ... either way the guys here have loads of troubleshooting ideas.

[ndutton]

Not a guaranty but I'm doubting it's fuel related due to instant restart. My first reaction is a questionable ignition connection or wire. Try running with a temporary jumper wire between the battery positive and the coil positive. Two cautions with this test arrangement: the only way you can shut the engine off yourself is to remove the jumper wire and if it stalls on its own, remove the wire immediately to avoid damaging the coil.

Under no circumstances should the jumper wire be in place if the engine is not running. A few seconds is OK. The jumper configuration I like is minimum 14 gauge stranded wire with alligator clips on both ends. The clips make installation and removal a snap.

Have you eliminated the dreaded Catalina trailer plugs?

[Mo]

Good, Neil is on here...he's you electrical guru.

[BunnyPlanet169]

I agree with Neil on this - the instant restart/run is unlikely if the fuel system is the culprit.

?... and if it stalls on its own, remove the wire immediately to avoid damaging the coil.

Or rather, remove the wire from your now, most likely, previously damaged coil.

If it runs well with the jumper, at different RPM and times, look to the plug/harness. You'll want to replace it anyway if you haven't already.

[gregsails]

Hmmm. Electrical. That never occurred to me. As it happens, I also bought a new coil at Moyer. I was waiting till I had everything working just right before I started adding new stuff as a just in case.That way I could tell if it was a new problem with the old gear. I ll install the new coil and see what happens and go from there.
As for the trailer wires... mine were in perfect condition lol. Im on the Great Lakes, Lake Huron.This enviroment isnt nearly as nasty as what you have to deal with. I lubed them up and put them right back to work.
Greg

[ndutton]

It could be the coil but it has not been determined definitively yet. Your symptoms do not include the typical coil failure cool-down period required before restart.

The jumper wire test eliminates or condemns the entire ignition wiring system, essential information at this point.

[BunnyPlanet169]

It could be the coil but it has not been determined definitively yet. Your symptoms do not include the typical coil failure cool-down period required before restart.

The jumper wire test eliminates or condemns the entire ignition wiring system, essential information at this point.

I jumped the gun. You are correct, sir!

[ndutton]

I jumped the gun. You are correct, sir!

Not to worry, you may end up being on the mark. Even though the symptoms don't match exactly, the coil is not off the table yet. Neither is fuel but I'm going with the symptoms provided for the time being.

[Dave Neptune]

Basicx

Greg, what is the fuel pressure at the carb? Low fuel pressure can keep the bowl full enough to idle but produce no power, this also fits your scenario.

You can eliminate the ignition system with a "hot wire" and you can eliminate the feul supply with the "pressure gage". Both are excellent checks.

Dave Neptune

[joe_db]

This would help

[ndutton]

Dang Joe, why didn't I think of that? Must be slipping. You're right, it would have answered the ignition wiring and fuel pressure questions instantly, two of the five monitored parameters.

[gregsails]

Update. None. I changed out the coil and motor still runs, no issue. Waves are so big right now I ll have to wait to get out.Wind is suppose to shift tonight to a better direction in case I lose the engine going through a 30 yard cut with rocks on each side. Not where you want to have no power. Need a sail up just in case.
Greg

[gregsails]

Hey All.
I have just retested by C 30 with the new coil. Same old thing. Runs fine in the slip but off the dock and under load it stalls out. It still does immediately restart, go for a while and then stall again.
My next step should be.......

Oh. I was just reading Mo s blog about his boat stalling and was thinking of fuel mixture. A friend that I trust had set mine when we were getting the motor ready the first time. But I would like to check it.

I understand the turn and a half from the start position. This may seem dumb but the start position of the needle is full turned ..... clock wise to start, thats the closed position and then a turn and a half counter clock wise to set it. Is that correct.
Greg

[Marian Claire]

"I understand the turn and a half from the start position. This may seem dumb but the start position of the needle is full turned ..... clock wise to start, thats the closed position and then a turn and a half counter clock wise to set it. Is that correct."
Yes. Gently turn clockwise until seated, you will feel it stop, that is the starting point, do not force it further then back out counterclockwise.
Dan S/V Marian Claire