Fuel starved?

[Liberator 6]

All,
Got a new QJet carb in, and installed it, no problems except the fuel line from the pump to the new carb was a little too long so I had to remove the pump from the holder and it's "hanging" from the mandrel bent steel line (pump to carb) from the top, and supported from the fuel inlet hose on the bottom. There is not much pressure on the pump at all, it seems quite content but I know that's not the "right" answer. I decided to give her a whirl, and the boat ran great for about 2 minutes and then seemed starving for fuel, both at idle and WOT, in gear and out. Sounds like fuel filter to me, any other ideas? How about suggestions for a new fuel line that's 1 inch shorter? Should I cut and flare it myself?

Thanks,
Rob

 

[Sorrento 25]

Re: Fuel starved?

Pull the pickup tube out of your tank and check the screen at the bottom. Mine had a small hemispherical screen stuffed in it with almost not surface area and it was plugged enough starve the carb for fuel after a period of time at cruise.

 

[180shabah]

Re: Fuel starved?

Should I cut and flare it myself?

That would be the best way.

 

[HT32BSX115]

Re: Fuel starved?

I have had my tank out a couple of times.

There IS a very small screen at the end of the pick up tube that is the same diameter of the tube. A terrible way to do it. It would plug VERY easy.

I will say....even though this boat was used a lot in the nearly 20 years my brother had it the tank was pretty clean. The screen was completely clean also.

Be sure to take a look at the anti-siphon valve that the hose to the tank is connected to. It's screwed right into the fitting at the tank. If that check ball is stuck it would cause the problem you're having.

You will be fine making your own fuel line using a flaring tool and tubing bender.

When it's running good what sort of WOT speed do you get?




Regards,


Rick

All,
Got a new QJet carb in, and installed it, no problems except the fuel line from the pump to the new carb was a little too long so I had to remove the pump from the holder and it's "hanging" from the mandrel bent steel line (pump to carb) from the top, and supported from the fuel inlet hose on the bottom. There is not much pressure on the pump at all, it seems quite content but I know that's not the "right" answer. I decided to give her a whirl, and the boat ran great for about 2 minutes and then seemed starving for fuel, both at idle and WOT, in gear and out. Sounds like fuel filter to me, any other ideas? How about suggestions for a new fuel line that's 1 inch shorter? Should I cut and flare it myself?

Thanks,
Rob

 

[Reel Poor]

Re: Fuel starved?

All,
Should I cut and flare it myself?

Thanks,
Rob

Thats easy enough. BUT, you MUST use a double flare tool. A single flare will not seal properly.

 

[Liberator 6]

Re: Fuel starved?

When it's running good what sort of WOT speed do you get?


Only about 50 MPH given the right conditions, wind and water chop. For some reason I'm thinking it's a 21 pitch prop.

I'll check the fuel pickup hose in the tank and replace the filter, as well as cut and use a DOUBLE FLARE tool for the new connection point.
Thanks!

 

[Liberator 6]

Re: Fuel starved?

I took the removable floor section out to get to the tank, and pulled the fuel inlet hose. There is in fact a screen there, totally unclogged. I blew air thru it with no restriction. I replaced the fuel filter, which also seemed equally clean inside but ran out of time for a water trial. At least I got a chance to pull the fuel float so my gas guage will work...

 

[Liberator 6]

Re: Fuel starved?

Is there a way to test to see if the fuel pump is kicking the right pressure? I am going up there today and I'm hoping that the new fuel filter will solve the problem, but since it was an intermittent sputtering problem I'm not completely sold on the fuel filter solution. As always, THANKS!

 

[Haut Medoc]

Re: Fuel starved?

Read this:
http://forums.iboats.com/showthread.php?t=167561....​

 

[Don S]

Re: Fuel starved?

Is there a way to test to see if the fuel pump is kicking the right pressure?

Sure, get a fuel pressure gauge at your local auto parts, make yourself a hose between the carb and the fuel pump to replace your metal line. Then put a tee in the hose to attach your gauge and run the engine. Check the pressure when it's acting up.
Also try this, you will use the same gauge.
http://forums.iboats.com/showthread.php?t=167561

 

[HT32BSX115]

Re: Fuel starved?

Well the obvious way would be to put a gage on it and measure it. Just make up a temporary fuel line using marine type flexible line and put a gage inline.

Once you determine that the fuel system is not clogged somewhere it may be the fuel pump or it may even be the new carb.

You know, if it starved at WOT it probably wouldn't "starve" at idle since the fuel flow is FAR lower at idle.

Did you have an anti-siphon valve at the tank?

 

[Liberator 6]

Power would be the problem

Power would be the problem

All,
Everything you mentioned sounds great, but the #1 problem is there is no power getting to the fuel pump with the ignition in the on position. I traced the wire backwards, and ended up with an impass at attached picture #1. I have no idea what this part is or what it does, but there is power going into it and not coming out the other side. It is a round part to the left of the brass fitting, two blade-type connections, obviously one in and one out, near the distributor.

Whilst searching for loose electricity, I found that the main breaker (see pic #2, and pardon the lack of an official term) is "missing" a wire as well. I did manage to find a loose brown wire laying in the bilge that lead me into the outdrive via the transom. Does this brown wire connect to the "absent" connection on this main breaker?

I'm still trying to find out why the high temp alarm doesn't sound off when you leave the ignition on like it used to. I have a feeling that this wiring business is really screwy.

I'm beginning to discover all the half @ss work my engine replacement guy did when it came to wiring, and I FREAKING HATE chasing loose electricity... Does the SELOC manual have COMPLETE wiring diagrams???

Thanks in advance for
a) Identifying the parts in the pictures
b) Telling me if the brown wire goes to the main breaker

Nearly ready to sink the damn thing -
Rob

 

[Don S]

Re: Power would be the problem

Re: Power would be the problem

Everything you mentioned sounds great, but the #1 problem is there is no power getting to the fuel pump with the ignition in the on position.

Well Gee, don't you think that might have been something to mention in your original post? A 1987 or 86 engine didn't even have an electric fuel pump.

Whilst searching for loose electricity, I found that the main breaker (see pic #2, and pardon the lack of an official term) is "missing" a wire as well. I did manage to find a loose brown wire laying in the bilge that lead me into the outdrive via the transom. Does this brown wire connect to the "absent" connection on this main breaker?

That is NOT your main breaker. It the Mercathode, which is part of your corrosion control system. The brown wire may be a brown wire with a white strip which is for the trim gauge, or it may be for the bilge pump.

I'm still trying to find out why the high temp alarm doesn't sound off when you leave the ignition on like it used to.

Probably because there is no Hi Temp sender sending a hi temp message cause it's cold. May be that you have a low oil pressure alarm switch that is either not working or not hooked up.

Does the SELOC manual have COMPLETE wiring diagrams???

The Seloc manuals don't have a COMPLETE anything. What you need is an OEM manual for whatever engine you actually have and some time studying it.
And that is going to take a Merc serial number or and engine year and model number.

 

[Liberator 6]

Re: Fuel starved?

Don,
Thanks for the info, I should have said it has an electric pump which the installer put in when he put the new engine in. Picture #2 is the mercathode to control corrosion, got it.

What is the circular "thing" next to the distributor in the other picture where power is being stopped from getting to the fuel pump? I traced power with the ignition on thru the starter and all the way around the boat to that part (first picture).

The reason I said the alarm isn't going off is because normally, if you put the ignition to the on position for more than 10 seconds it tests the alarm and it sounds. You said previously it's supposed to be a brown and green wire which I can't find anywhere... Right now though, that's the least of my problem.

Thanks,

 

[Haut Medoc]

Re: Fuel starved?

Oil pressure switch.....
When you put the key in the 'start' position, the pump will run, the engine starts, key returns to run position, oil pressure builds, closes the switch, fuel pump runs.......​

 

[Don S]

Re: Fuel starved?

 

[Liberator 6]

Re: Fuel starved?

Oil pressure switch.....
When you put the key in the 'start' position, the pump will run, the engine starts, key returns to run position, oil pressure builds, closes the switch, fuel pump runs.......​

Are you saying that the fuel pump shouldn't get power until after the engine is started? This could be a MAJOR flaw in my diagnosis, but if the oil pressure switch is dead that could be why the oil pressure alarm buzzer isn't working...

 

[Don S]

Re: Fuel starved?

Are you saying that the fuel pump shouldn't get power until after the engine is started?

That's correct.
It's a safety issue. You don't want the fuel pump running if the ignition switch is left on and the engine not running.

but if the oil pressure switch is dead that could be why the oil pressure alarm buzzer isn't working...

Nope, the oil pressure switch for the alarm works opposite.

 

[Haut Medoc]

Re: Fuel starved?

But it will/should pump with the key in the 'start' position......
Then the engine starts, the key returns to 'run', pump shuts off, oil pressure builds & closes that switch & pump runs......
Like Don said, it is a safety feature.....​

 

[Reel Poor]

Re: Fuel starved?

Note Dons wiring diagram above. The purple/yellow wire from the starter supplies power to the fuel pump while cranking. Once it's running the the oil pressure switch closes (due to oil pressure) and power is connected from the purple wire to the purple/yellow wire leading to the fuel pump.