Dies Suddenly while Cruising

[Andy R]

Got it removed. Thanks for reporting it.

[JoDo]

Put the new thermostat in. The one it called for is a Sierra 18-3668 which is 142° and the engine warmed up to 150° then hung out at 140° . I hope this is it, I won't know until out on the lake though. The carb "icing" thing sure seems logical the way I saw water pooling on the carb. Thanks all, I'll update when I know.

[Kevlar7r]

Hope that solves it for you.

When I was having problems with my previous boat, my issue was the oil/water foam (aka milkshake) in the breathers. No evidence of water in the oil pan, but milkshake blowing out the breathers....

My neighbor was this old crusty mechanic who sat on the tailgate of his truck every night and drank a glass of vodka.

One night we were on his tailgate, I with my scotch, discussing this, when he asked me my engine temp.

Long story short, that engine ran like a champ for 3 more years till failed exhaust manifolds destroyed it.

Send your thanks to Dan, drinking his vodka on the tailgate.

[JoDo]

Just finally got back to my boat. Life was getting in the way for a week or so. After the thermostat change I took her back out. Same stalling issue. Happens like clockwork, really. However, no water build up. I am definitely dealing with a loss of fuel. I pulled the separator after the stall and it was only about 7/8 full of fuel, no fuel at the top and no fuel squirting from the carb. So tonight I pulled the pickup tube and here's what I found. There is barb fitting with a check ball and it was really gummed up. The ball was stuck with varnish. I think I would get enough fuel through there to idle and even run at 3000 rpm with no load but once I am in the water and have a load I lose fuel pressure because of all that gunk around the ball.

[mmwjr]

That's the anti-siphon valve to prevent fuel from being sucked out of the carb back into the tank when not running. Yes they fail either by blocking fuel flow or stick open. I would replace it.

[oldno7]

I didn't bring it up here but did in another thread, I knocked the ball out of the anti-syphon valve and it fixed my high end stalling.
Hope that fixes yours.

[mmwjr]

Originally Posted by oldno7

I didn't bring it up here but did in another thread, I knocked the ball out of the anti-syphon valve and it fixed my high end stalling.
Hope that fixes yours.

Common solution, also they make one ball less.

[oldno7]

Originally Posted by mmwjr

Common solution, also they make one ball less.

lol

My boats a she, anyway--don't need no stinkin' balls......

[mmwjr]

Originally Posted by oldno7

lol

My boats a she, anyway--don't need no stinkin' balls......

Well just roll that ball out of here.

[JoDo]

I wanted to make a Lance Armstrong joke but did not want to offend anyone.

[JoDo]

Changed fitting and it started and ran well (in the driveway). It did stall once and it seemed to have no fuel. I gave the throttle a pump and no squirt. I also pulled the line from the tank to the separator and it was full of fuel so I believe it's pulling from the tank fine. I gave it a small shot of ether and it fired right up and ran. For experiments sake I shut off while running fine and pumped the throttle and still no squirt. Am I under the wrong assumption that I should see a good shot of fuel? I feel the accelerator pump is working because when running I can give the throttle a good romp and no hesitation. Also, under normal operation should the fuel/water separator be plumb full? When I remove mine after shutting off the engine normally, it is about 3/4 full.

[mmwjr]

Yes you should see it squirt so the accelerator pump is not working or the ports are clogged.

Have no idea about the level in the filter as I have not paid that much attention when changing mine.

[ss3964spd]

I think at this point I would by-pass as much of the boat's fuel system as possible.

Set up a temporary 5 gal tank on the deck and run a fuel line from it directly to the input of the pump. Make sure the temp tank has a vent, or place it in a larger container to contain any spills and leave it open where the fuel line goes in.

If it runs fine with the temp set up the issue is between the pump and the tank, if the same symptoms present themselves it's the FP or carb.

It almost seems like the carb float is somehow getting stuck in the closed position intermittently.

Another thing you could try when you find there is no squirt when you pump the throttle. You can fill the carb fuel bowl through the bowl's vent tube using a small syringe and small diameter length of hose. Inject about 1/2 cup of gas then immediately see if you get a squirt.

Dan

[JoDo]

Yes there was definitely a problem with the accelerator pump

I can't blame the shop that rebuilt the carb, that was all me. I had taken the top off to check the fuel in the bowl and apparently mangled the seal in the process of putting it back together. Everything seems to be running as it should now and will hopefully get it out soon to test.

[JoDo]

Well, took her out for a successful run today. About 4 miles overall and no problems. Well one unrelated issue with the pump for the outdrive tilt but that will be another thread. It looks like that gunked up anti siphon was the problem all along. At least all the other things I fixed needed to be done regardless. Anyway, thank you everyone for all the input.