Fuel pump/pressure?

[CaptainTerry]

Hey everyone! I have gotten a lot of advice from this forum and most of it has been good. But I have a fuel problem I can't figure out (YET).
A year or so ago I removed the VRO oil tank and line and plugged the pump (oil side) because I had been having a lot of trouble with it under oiling and over oiling on the advise received here. I now mix my oil in the tank and it seems to be fine.
Since last year I have had to continually pump the bulb on the fuel line. It will run fine for 15-20 minutes, then looses pressure agin requiring to be pumped up. It's a bit of a pain, but in bad weather it's worse as you can imagine. My wife was having to pump it as the wind pushed us sideways under a stalled out condition. We were trying to get off the lake as a storm approched. Now I am very seriously wanting to repair because of this incedent which I feel is a safety issue.
I have replaced the fuel ine and bulb, and my next guess is the pump but I am not sure this will solve the problem
Any help would be a help!

 

[tashasdaddy]

Re: Fuel pump/pressure?

replace the pump, not knowing what engine you have, but since you disabled the vro, go with the gas only pump, and save a few bucks.

 

[CaptainTerry]

Re: Fuel pump/pressure?

trashdaddy:
Sorry forgot to mention it's a J/E 70 hp 1980
Think the pump is the culprit? How much does a fuel only pump cost and what PN do I get that will match up and replace the existing VRO pump?
Thanks CaptainTerry

 

[ezeke]

Re: Fuel pump/pressure?

All any fuel pump does is lift fuel from the tank to fill the float bowls and provide fuel for the primer. If there is any obstruction or air infiltration in the tank or along the line before the fuel pump, you can have the same conditions that you describe.​

The quickest test is to use a known good portable tank with a totally different fuel line.​

If you wanted to you could take the motor to its original conventional fuel pump #385784 now superseded by #438,559 at least cost, but you may want to try a different tank first.​

If you want the more complex premix fuel pump that looks like a VRO, but isn't, you can get one for approximatel three times the cost of the conventional pump. part #438402.​

If you use the conventional pump, you would need to plug one pulse port. and open the other one where the fuel pump mounts.​

 

[Kevin W]

Re: Fuel pump/pressure?

The fuel pump is definately a possibility.

I would also make sure your fuel line is not sucking air.
alot of VRO problems are not the VRO but the fuel line or tank.
if it is pulling air in the line it will create nightmares with the mixture and after you disconnected it it would work ok but may loose prime or run lean at higher speeds.

1980 did not have VRO's...are you sure its 1980?

 

[CaptainTerry]

Re: Fuel pump/pressure?

Kevin:
Fairly sure it's a 1980 but not positive it came original as far as I know only one other owner (unless an untruth was told) on a 1980 LOWE 1700V hull
I suspect air being sucked, but don't know from where. The fuel line does not leak any fuel, or at least I can't smell any. so I am asuming air is being let in at a higher point (fuel pump)?

 

[CaptainTerry]

Re: Fuel pump/pressure?

EZEKE:
thanks for the PN's
I suspect air inflitration too
do not have another portable tank to test with
Since the fuel tank is lower than the fuel pump if there was a air leak there wouldn't fuel be leaking also? Never smell any fuel!

 

[ezeke]

Re: Fuel pump/pressure?

You would probably see a fuel leak above the bulb because you are putting pressure on it. You would probably not see a leak below the bulb because you are creating a vacuum. You would not see an air leak in the pickup tube in the tank if it has corroded.

You would not see a bad primer bulb, an obstruction in the fuel line, or a stopped-up anti-siphon valve; if they exist, the pump cannot overcome them.
​

 

[Kevin W]

Re: Fuel pump/pressure?

check your serial # and look here
http://www.maxrules.com/OMC_models.html

The motor is most likely newer than the boat if it has a VRO

 

[jeeperman]

Re: Fuel pump/pressure?

Air HAS to get into the tank or else a vacuum will form and your pump won't be able to pull fuel. Your air infiltration may be anywhere from the from the tank bottom and up stream.
You could always pull the hose off the bulb upstream, connect a couple of feet of new hose to it and stick the end into a 5 gallon fuel jug for the line leak test. As well as anti-siphon valve test.

Your tank vent could also be obstructed enough that the pump can not pull the fuel but the primer bulb can.

 

[CaptainTerry]

Re: Fuel pump/pressure?

Thanks everyone:
I intend to check all these ideas out, better get er done!
CT

 

[CaptainTerry]

Re: Fuel pump/pressure?

what is an anti-siphon valve and where is it located?
I have never seen the fuel line pick up in the tank, it's below the deck of the boat somewhere

 

[clemsonfor]

Re: Fuel pump/pressure?

Like the others have said use another portable tank, like a small red 6 gallon one if you don't have one (which you said you don't) try and borrow one from a fried from his working jon boat or if you are not cheap like most of us you can go to walmart and buy one for $25 or less! This will eliminate the pickup, the antisiphon valve and if the buddy let use use his line the line and bulb. Oh the anti siphon valve is at the tank where the line connects to it and keeps the gas from flowing back into the tank when the motor is off, and according to the experts is where lots of problems exist and trash gets stuck creating a problem.

-nate

 

[ezeke]

Re: Fuel pump/pressure?

Coast Guard regulations require that built-in tanks have anti-siphon valves on the outgoing fuel fitting. This is to prevent the fuel from being siphoned from the tank if there is a leak at the hose or engine.

The anti siphon valves are mostly of the type that have a ball bearing with a spring. The older ones are designed for inboard type installations, not outboards, and they are not designed for today's fuels. In addition, they are prone to sticking, causing poor fuel flow.

Regardless, the fuel system has to overcome the pressure of the valve in addition to lifting the fuel.

The bottom line is that if all of the outgoing fuel lines and the engine are higher than the top of the tank, the anti-siphon valve can legally be removed. If not, it is good practice to replace them with the newer ones.

If you take the tank fitting off and find that there is no valve inside of it, you can move on to the fuel line and bulb and so on.

 

[CaptainTerry]

Re: Fuel pump/pressure?

EZEKE:
Thanks for the info
I have already replaced the fuel line and bulb, from I-Boats online store.
To my dismay, it didn't solve the problem.
I am going to check that A/S valve next
TH