351 carb engine schematic

I run a can of "Sea Foam" through my 1984 SN2001 every 50 hours. I also use "Sea Foam" as a stabilizer when I winterize my boat. Personal experience has made me a huge fan of the product.

Whoever takes drain oil might take your old gas too. There are couple garages around here who run waste oil heaters, we get landscaping services in return for our oil! The solution to pollution is dilution.

So i pulled the line at the bottom of the fuel pump and put a new one on which I ran in to a fresh gallon of fuel. It hiccuped a bit but then started to run fine. The only problem was it died when put in neutral.

This may be an effect of not running enough good fuel through yet it but either way the old fuel did smell like paint thinner so that was at least part of my problem. Any advice on draining 20gal of fuel?

Once again thanks for the great advice.

The feed line going to the fuel pump is 3/8" ID.

by bypassing the tank you take problems at the tank out of the equation and narrow it to the fuel pump or carb. Another think to check is if there is a filter between the pump and carb, and this encludes one that might be in the carb, but they need replaced this can cause a flow issue as well as that is what seems like your problem is.

Ill check those options tonight. Thanks for the info.

DrCC wrote: Trick for the "hardline" at the carb. Line wrench 1" wrench or maybe a cresent PB Blaster and possibly a small hammer

leave the hammer for your head and not the carb.

the trick is tightening the flare nut slightly before loosing it, 5/8 line wrench for the fuel line, 1" line wrench or open end to hold the carb's fitting, once the line is loose then use a 6 point socket or a 1" line wrnch to remove the other fitting put that is only if your replacing the filter if not there's not a need to remove it from the carb.

I can see fuel spraying into the carb when I work it by hand at the carb as well as when I advance the throttle. Things seem to be pointing to more of a fuel issue.

Just to recap when this problem first occured a few weeks ago I was taking the boat out for the first time in 2 months and before launching I added about 10 gallons of fresh fuel. The boat started and idled for approx 5 min and then abruptly died. Since then this starting and quickly dying (within 2 seconds)problem has persisted.

If it runs with starter fluid, then youre correct- you have a fuel delivery problem. You can put away the multimeter... for now!

Where are you seeing fuel going to the carb? Hopefully you dont have a rubber hose with an inline filter between the pump and the carb... thats a big safety no-no.

Pull the flame arrestor and work the carb by hand- if it sprays fuel when you advance the throttle, then youve got gas. If that wont keep it running, then Id say you have bad gas. If you dont have gas, then you need to trace the problem back to the source. The 2 likely culprits would be a bad fuel pump, or a blocked fuel line (look at the antisiphon valve first).

bubbaskier, welcome to the site.Great place to learn and to share the do's and don'ts of inboard boating.
But be forwarned as to info you post,"my brother told me" and " I heard you could do it that way" are not valid here.
You will be called out on misinformation, and applauded for that little short cut you dicovered.Please share, pics ,info,listing for junkers and all CC issues...........Billy

bubbaskier wrote: Anti-Syphon Check Valve Somewhere from the fuel tank to the fuel pump should be an anti-syphon valve. On my 1984 SN2001 the valve is on the fuel tank. This valve allows fuel to flow in only one direction. Find the valve, remove the valve and see if there is any debris in the valve restricting the flow of fuel. I have had to clean mine once in sixteen years. Also the springs in these valves do wear out allowing the gas in the fuel line to syphon back into the tank causing starting problems, ie: lack of fuel.

Corky,
Welcome to CCfan. Tell us more? Boat?

Now, you actually have the operation of the anti-siphon valve backwards. No big deal as I was corrected once as well. The anti-siphon is there so if there is a break in the fuel line from the tank to the fuel pump, you won't fill up the bilge with gas. It checks the siphon but isn't stong enough to check the pull from the fuel pump. Gas siphoning back to the tank is prevented by the internal check valves in the pump itself.

HHHMMMM it's 99 wouldn't the fuel control cell's and the relay's be a better place to start than the ignition?

Texasttk55
Sounds like the ignition has power when the key is in crank and not in run.

Ok so I have checked spark and it seems very strong. Checked vacuum at the bottom of the fuel pump, it also seems strong.
The only thing that I cant check is fuel pumping out the top of the pump into the carb because I can't seem to losen th efitting running from the hard line into the bottom of the carb.

Is there a trick to this without bending that fuel line? Also if fule is in the line can it be assumed that the top side of the pump is working? I can see fuel spray into the carb when I manually push the throttle cable and when the actual throttle is pushed forward. The engine fires up but only runs for a split second. This seems like a fuel delivery issue but I cant figure out were the problem is occurring.

Any ideas? Thanks for the advice.

- Travis

Take a quick look at the filter that is built into the fitting where the gas line goes into the carb. It can plug and create the symptom you are describing.