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Mercruiser fuel starvation

A

alexdyer

Contributing Member
"I have a 4.3 efi merc
the pr

"I have a 4.3 efi merc
the problem is that it will start up just fine but if i stop it for half an hour, when i go to start it again it only cranks over!
Thinking it might be a fuel problem I took off the fuel hose and sucked the petrol up the pipe then put it back onto the fitting and it started up just fine! Thinking this might have been a one off i have tried it since and sucking on it works every time. any ideas? is my pump not working as well as it should be?
Or is this a vapour lock that i have read about? if so what causes one?
Any help would be greatly appreciated.
Alex
United kingdom."
 
"How's that petrol taste?

"How's that petrol taste?
Check your tank vent. It sounds like it may be plugged.
Any other restrictions or places where air can get into the tubing from the tank to the pump?
Is there a filter before the pump? If so, is it clean?
If all this is good, you may want to change the fuel pump out.
Just some thoughts.
Rod"
 
mmmmm petrol.

If I'm no

mmmmm petrol.

If I'm not mistaken this has a recirculating fuel system with a fuel pressure regulator like cars do. I would put a guage on it to make sure you have the right system pressure. Also make sure the fuel line is not exposed to heat.

what are fuel prices in uk these days?

cheers
 
"Vapor lock arises from the fa

"Vapor lock arises from the fact that fuel pumps only pump liquid well, and really suck (pun intended) at pumping fuel vapor. You get vapor lock either from heat - too much heat on the fuel suction line to the pump, or from the pump sucking thru a restricted line. In both cases, the fuel actually boils, creating fuel vapor bubbles in the line.

EFI fuel pumps are very bad about self priming, which is why they are usually in the tank (also to deaden pump sound). I'm not familiar with your setup, but if the pump is not in the tank, the check valve inside the pump (which keeps the pump primed up on engine stop) has failed or is jammed open. Or the filter sock on the fuel pickup is clogged up, restricting fuel flow on the suction side. You rarely manage to get vapor lock on the pressure side of any fuel pump, and almost never on a high pressure efi pump.

Heat induced vapor lock can be field fixed by dumping water on the hot fuel line. Vacuum induced vapor lock can only be fixed by removing the flow restriction in the fuel suction path. Heat + vacuum vapor lock "may" be cured with the water dump, if the flow retriction is small.

Loss of prime problems can be cured with the addition of a new check valve in the suction line just before the pump, or with an electric "priming" fuel pump just at the tank outlet IF you have an efi pump external to the tank."
 
ok not sure if it has a regula

ok not sure if it has a regulator!
it has one pipe from the tank going to some kind of canister on the left hand side of the engine then pipes going underneath to the right hand side.possibly a pump?
When I fill up the tank I have to be really slow as the pressure in the tank stops the flow from the pump and makes it click off. is this a good indication of blocked breathers? Now i have typed that it seems pretty obvious.i'll look at them over the weekend.

Oh MistaHays a gallon of unleaded costs £4.90 at your own marina and £5.30 as a visitor.
So approx $10.40 and $11.07
We get ripped off something rotten over here mate! I bet yoursis half that hu!
Thanks for the info i'll get back to you.
 
Alex:

Rod told you to "

Alex:

Rod told you to "check your tank vent. It sounds like it may be plugged."

You said "When I fill up the tank I have to be really slow as the pressure in the tank stops the flow from the pump and makes it click off."

I agree with Rod's comment and the others' also. Look at the vent hose for a kink in it or a low spot in the line where liquid gas could get trapped. The fuel pump can't pump when the liquid is there and you can't fill the tank when its there.

By the way; my aunt was married to John C. Dyer born in England about 1900. His parents were originally from Ireland. Geneaology is my hobby.
 
"Guy

I thought boats were y

"Guy

I thought boats were your Hobby.

Alex
I am with the others, your description sounds a bit like a blocked vent system. If you want to confirm it without pulling your boat apart take your boat for a run and leave the fuel cap a little loose so that the tank will vent easy
If the problem does not occur with the cap loose then you probably have a blocked vent.

Cheers
Peter C"
 
we're paying $3.99 a gallo

we're paying $3.99 a gallon. What drives up the price for you (and me to a lesser extent) are taxes. cheeers.
 
Average Australian bowser pric

Average Australian bowser price is around $1-37 per litre.
Considerably dearer than that at any marina unless you purchase over a few hundred litre's then they will normaly knock a small amount off the price.
We are expecting the price of fuel to head up to around the $1-50 per litre in the next few weeks as the price per barrel of crude has gone through the roof in the last few weeks.

And you guys reckon you have it bad.

Cheers
Peter C
 
"Peter:

Do your tax laws al

"Peter:

Do your tax laws allow you to deduct part of your boating costs as legitiment business expenses if you take a customer out. Let's say you fly me, Rod, FastJeff and MistaHays over to OZ for a weekend business meeting on the tug and we chug a few. Couldn't you deduct the cost from your taxes?"
 
...."So approx $10.40 and

...."So approx $10.40 and $11.07. We get ripped off something rotten over here mate!"

That's because your funding a welfare state! It must give you a good feeling knowing you're helping all those "needy" people out there every time you fill up!

See how lucky you are!

Jeff
 
I feel warm and tingly every t

I feel warm and tingly every time i reach for my wallet!

I'm out on the boat today so I will try the open filler cap.

Cheers guys

Alex
 
"Guy
Many years ago we could

"Guy
Many years ago we could get away with lots of little rorts with our boats when we used them for entertaining our customers but the government wised up and changed all the rules.
As a result we have one of the most complex taxation systems in the world and it is very hard to get anything back as a deduction let alone any boat costs.

Unfortunatly my tax deductability on fuel is only applicable to my diesel ute too and seen I do not have diesel's in my boat I am out of luck.

However, I could claim flying you guys over for a weekend if you formed a consortium and said you were coming to australia with a view to check out my business as a possible aquisition as it is on the market.

I could tell the tax man that I agreed to fly you out here so you could investigate our operation in person.
There, that sounds like a ligitimate reason to me.
The only problem is I cannot afford the air fares or the drink bill if you guys came over.

Alex
Thank god for me that my criminal for fathers were sent over here by your country men to populate this island in the pacific that has beautifull boating weather all year round
wink.gif


Cheers
Peter C"
 
"Alex et al:

If you blokes

"Alex et al:

If you blokes have offshore oil drilling wells, what do you do with the oil? Make laxitives for the nation? Or sell it to the Euro nations at twice the price? Give me some stock mate! Here, here; keep a stiff upper lip and have some "SPOTTED DICK" for dessert. Cheers!"
 
"Guy
Its this playing on the

"Guy
Its this playing on the world market thing, we actually produce just about enough barrels per day to satisfy our consumption but because we are part of the world market we actually place our oil into the global market and then essentialy buy it back at an inflated price.
Then after the refining price the government adds about 75% of the final bowser price in various taxes.
They tell me that Australias main influence on fuel pricing is in the Phillipines and our fuel price fluctuations follow theirs but about 7 days after.
Anyway, fuel is a depressing topic as both my tanks are empty and I will need to get something into them in the next week or so before I re launch.

Cheers
Peter C"
 
Hysterical. Count me in on the

Hysterical. Count me in on the trip! I'll buy the scotch/bourbon/beers (and iced tea for ole Guy as i know he's on the wagon).
 
"I can feed you and keep the d

"I can feed you and keep the drinks (and tea for Guy) up for a couple of weeks, we could get in some good boating, fishing, and generaly clowning around done but I cannot afford the air fares so you are out of luck.

Mind you, there is always a warm bed and a feed as well as a cold beer and a fueled up boat if any of you are in the area.

You may just have to wait for a couple of more weeks until my floating money pit is back into the water again.

Cheers
Peter C"
 
"Hey! I'm allowed two oun

"Hey! I'm allowed two ounces of alchohol every 24 hours. Peter: Cant you pick us up in Florida with your cruiser? We'll need a few 50 cal. machine guns and mortars for the pirates. I think 25 RPGs will do. I can bring my 12 ga. slug gun and a case of 00 buckshot and a case of 1 oz. sabot slugs. Don't forget the booze, beer and ice, I'll be designated pilot although I didn't do well in reconoitering."
 
Just doing some rough fuel cal

Just doing some rough fuel calcs for the trip. With ULP at the price it is currently and the distance involved as opposed to my 500 litre fuel capacity I think it would be better and cheaper if I did just fly you first class.

Cheers
Peter C
 
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