No Fuel in Carb Bowl-gctid809982

[Fiftybucks]

When I try to start the boat after 3 weeks of sitting, it is very hard to get started. No gas in the carburetor. Pumping the throttle there is no squirt from the accelerator pump. The carb remains dry for several cranking episodes of 20 seconds. What does work is squirting a little fuel down the primaries. Engine fires up, then dies.. 3 or 4 times. I am thinking the fuel pump must be dry also, so the entire plumbing would have to be refilled with gas. When the boat does fire up it runs fine. no hesitation, accelerator pumps working etc. Why is it dry? Where did the gas go? No leaks, no drips, no smell.

The boat is a 95 with the 7.4 454.. and mechanical fuel pump. Mercrusier Rochester Quadrajet. Dock mates suggest to put on an electric pump. Is this an option? Are the mechanical pumps rebuildable?

[canoel]

Most likely it is the check valve in the fuel pump. Some are rebuild-able, but mostly just replace.

[builderdude]

An electric fuel pump can be added in place of the mechanical pump with the option to prime the system without having to crank the motor. To do this correctly it needs to be wired through a momentary switch (for priming), and then through an oil pressure switch as a fail safe to kill power to the pump if the engine quits.

IMO if It bleeds off in just 3 weeks it's probably the pump and/or anti siphon valve.

[Chief_Alen]

leaking well plugs ... some epoxy i urge people to use a kit. Do it right the first time.

http://www.hotrod.com/articles/hppp-...et-carburetor/

20 bucks !

[2850Bounty]

"Fiftybucks" post=809982 wrote:
When I try to start the boat after 3 weeks of sitting, it is very hard to get started. No gas in the carburetor. Pumping the throttle there is no squirt from the accelerator pump. The carb remains dry for several cranking episodes of 20 seconds. What does work is squirting a little fuel down the primaries. Engine fires up, then dies.. 3 or 4 times. I am thinking the fuel pump must be dry also, so the entire plumbing would have to be refilled with gas. When the boat does fire up it runs fine. no hesitation, accelerator pumps working etc. Why is it dry? Where did the gas go? No leaks, no drips, no smell.

The boat is a 95 with the 7.4 454.. and mechanical fuel pump. Mercrusier Rochester Quadrajet. Dock mates suggest to put on an electric pump. Is this an option? Are the mechanical pumps rebuildable?

[color]blue wrote:
I'm thinking that your 1995 engine should be equipped with an electric fuel pump. Are you certain that it is mechanical?

If it is electric:

During start-up, the start-by-pass circuitry is to operate the fuel pump in the absence of oil pressure. Once the starter motor is disengaged, this circuit becomes inavtive. By this time engine oil pressure closes the N/O low oil press sw and continues operating the fuel pump.

Use a test light or VOM to see if the fuel pump receives power during cranking only.

If not..... then you have an issue with the start-by-pass circuit.

And by the way, what Dave suggested re; the momentary helm swith does work, and it will prevent early starter motor failure and will extend starting battery life.

If it is a mechanical fuel pump, it may be time to replace it.

All that having been said........., your carburetor fuel bowl should not be dry after sitting for only several weeks.

Perhaps remove it just after operating the engine. Place it over a clean white paper towel. Look at the paper towel after it has been there for a few hours.

If it shows signs of leaking fuel, then it's likely the factory machining ports that had been closed off via epoxy that is now failing.

[/color]

.

[Fiftybucks]

After 4 days the boat started instantly. No issues and gas in the carburetor,

Where is the 'Check Valve'? what does it look like and can it be cleaned and re-assembled? I took pics of the fuel pump but left my phone on the boat.