Fuel prime

legendlc
Aluminum Star
Posts: 180
Joined: Tue Mar 01, 2016 6:50 pm

Fuel prime

Postby legendlc » Wed Jun 24, 2020 10:02 pm

Question about fuel here. In getting my 440's started for the first time in 12 years my engines have lost prime a few times. One being after I pumped my tanks out and now after the carbs were removed for rebuild? I spent 5 hours today with a mechanic and we primed the carbs a dozen times with a bottle of gas. Pumped the crap out of the throttles and I could never get the fuel line to pick up fuel from the tank. The engine would run as long as we were adding gas by hand but nothing at all when we stopped. Shouldn't there be a anti siphon valve to keep the lines from running back into the tank? Just seeing if anyone else has seen this? Previously when it happened I spent two days and finally was able to disconnect the fuel line, use a transfer pump to get fuel into the line and then finally after hours of tries the fuel pump picked up and it pumped like crazy. Is my pump bad? When it has fuel it sprays it across the bilge but it doesn't seem to get primed. I don't want to have to do this process every week if I'm gone for a week a two. Is it because the carbs were removed for rebuild?
1978 37 Double Cabin
Lake Cumberland KY

liquidplummer
Member
Posts: 17
Joined: Mon Jul 14, 2014 9:15 pm

Re: Fuel prime

Postby liquidplummer » Thu Jun 25, 2020 1:13 pm

I have had the anti syphon valve for the generator stick several times. They locate them right off the top of the tank, threaded onto a nipple coming out of the tank. Also make sure you have no leaks along the fuel lines. A pinhole can suck in enough air to stop the draw of fuel. Good luck
Silver Queen St Louis Mo
1982 37 ft flybridge sedan twin 360 chryslers 1.91 velvet drives

User avatar
Tuggle
Aluminum Star
Posts: 143
Joined: Sun Jun 26, 2016 4:42 am

Re: Fuel prime

Postby Tuggle » Fri Jun 26, 2020 4:22 am

Disconnect the fuel lines from the main tank and try running from a remote tank, if it runs replace your anti siphon valves. You sure your pumps are good after sitting for twelve years?
"Deplorable", 1975 32' Express, Twin 318's, Raw Water Cooled, Lake Lanier, Ga.

legendlc
Aluminum Star
Posts: 180
Joined: Tue Mar 01, 2016 6:50 pm

Re: Fuel prime

Postby legendlc » Fri Jun 26, 2020 7:00 am

Once primed the pumps will pump like crazy. This is the second time I have lost prime on them.
1978 37 Double Cabin
Lake Cumberland KY

User avatar
Tuggle
Aluminum Star
Posts: 143
Joined: Sun Jun 26, 2016 4:42 am

Re: Fuel prime

Postby Tuggle » Fri Jun 26, 2020 11:29 am

Put a primer bulb between the tank and pump. It will also give your starter motors some relief.
"Deplorable", 1975 32' Express, Twin 318's, Raw Water Cooled, Lake Lanier, Ga.

ddependo
Royal Aluminum Star
Posts: 279
Joined: Mon Jul 14, 2014 10:00 am

Re: Fuel prime

Postby ddependo » Fri Jun 26, 2020 12:21 pm

is primmer bulb an uscg approved item for inboard use??
1973 32 express fly bridge
Chattanooga
"Southern Lady"

User avatar
Tuggle
Aluminum Star
Posts: 143
Joined: Sun Jun 26, 2016 4:42 am

Re: Fuel prime

Postby Tuggle » Fri Jun 26, 2020 3:25 pm

Don't know but can tell you mine have been on for several years. After the boat has sat for extended periods I squeeze the bulbs until I can see pressure on the gauges and it fires right off. One thing I will say is crank it over several times before priming to get oil to the top of the engines, avoiding dry starts.
"Deplorable", 1975 32' Express, Twin 318's, Raw Water Cooled, Lake Lanier, Ga.

javalin390
Royal Aluminum Star
Posts: 323
Joined: Sat Jan 10, 2015 7:14 pm
Contact:

Re: Fuel prime

Postby javalin390 » Fri Jun 26, 2020 8:28 pm

Not sure if they were originally equipped with them, but mine has a set of stainless/bronze ball valves in each fuel line. I shut them off when the engines are off, never looses its prime. As liquidplummer stated, a pinhole could be a problem, you will never notice fuel leaking, but it will let in just enough air to loose prime. Used to see that all the time back when I was wrenching on trucks working for Caterpillar.
Jim Elias
1974 37' SedanFlybridge
Twin 360 Chryslers.
Marblehead, Ohio

legendlc
Aluminum Star
Posts: 180
Joined: Tue Mar 01, 2016 6:50 pm

Re: Fuel prime

Postby legendlc » Fri Jun 26, 2020 10:20 pm

I got it primed back up finally. I will try shitting the valve off on top of the tanks if I am not going to be cranking her for a few days. Carbs back on now so hopefully I will be good.
1978 37 Double Cabin
Lake Cumberland KY

mboat1
New poster
Posts: 2
Joined: Mon Dec 30, 2019 7:12 am

Re: Fuel prime

Postby mboat1 » Wed Jul 01, 2020 3:39 am

replace the pumps,dont get out there with pumps that have set up dry that long ,your asking for trouble. (mechanic?) hmmm