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peterb
08-02-2006, 12:40 AM
I have an 86 with a 351 and a 4160 carb. Prior to rebuilding the carb I had a problem with stalling at idle once warm and at tubing speed, it would drop out and stall then not be able to start.

I rebuilt the carb and seemed to correct the warm engine stall in idle. But, I still have a problem. Around 30-35 mph the engine will stall out after running for a few hundred feet.

Today we tried it with the engine cover off and the flame arrestor off. As it started to stall out, we hit it with some starting fluid and it came back to life then stalled out again. We kept it running with starting fluid which points towards starving for fuel.

To rule out a plugged airvent on the fuel tank (as someone suggested), we drove with the gas cap off and still had the problem.

So, I guess at this point, because it happened before and after the carb rebuild, it points to something else... maybe the mechanical fuel pump?

Prior to using the boat this year, we drained the fuel tank and cleaned it out as well as putting in a new fuel/water seperator filter element. Is there another filter I am missing?

Is there a way to "test" the fuel pump before I buy a new one.

Any other suggestions?

madison
08-02-2006, 01:54 AM
I have an 86 with a 351 and a 4160 carb. Prior to rebuilding the carb I had a problem with stalling at idle once warm and at tubing speed, it would drop out and stall then not be able to start.

I rebuilt the carb and seemed to correct the warm engine stall in idle. But, I still have a problem. Around 30-35 mph the engine will stall out after running for a few hundred feet.

Today we tried it with the engine cover off and the flame arrestor off. As it started to stall out, we hit it with some starting fluid and it came back to life then stalled out again. We kept it running with starting fluid which points towards starving for fuel.

To rule out a plugged airvent on the fuel tank (as someone suggested), we drove with the gas cap off and still had the problem.

So, I guess at this point, because it happened before and after the carb rebuild, it points to something else... maybe the mechanical fuel pump?

Prior to using the boat this year, we drained the fuel tank and cleaned it out as well as putting in a new fuel/water seperator filter element. Is there another filter I am missing?

Is there a way to "test" the fuel pump before I buy a new one.

Any other suggestions?

so it runs good until the secondaries kick in??? im having similar issues with my 89 ps190.. not as extreme, but thinking I am going to have to replace the carb

Jesus_Freak
08-02-2006, 03:31 AM
Extra filters: Check the carb fuel inlet port, as well as the rubber hose leading from your tank to the inlet of your fuel pump.

Fuel pump: Disconnect the fuel tubing downstream of the pump and check the discharge pressure with a gauge.

peterb
08-02-2006, 10:31 AM
Watching in the carb, this is before the secondaries kick in.

Before the inlet on the fuel pump is the fuel/water seperator/filter. We replaced that element.

Didn't see a filter on the inlet port of the carb when we rebuilt it.

If I disconnect the fuel line from the pump and check the pressure, then I assume that is just cranking because there won't be any fuel in the engine to fire (it's a mechanical pump)? What should the pressure be? Where can I find a gauge?

BrianS
08-02-2006, 06:24 PM
I just solved a similar problem with my '93. Here is a link to the thread with some tips and pictures.

Link (http://www.tmcowners.com/teamtalk/showthread.php?t=9783)

Also, if you still have the original mechanical fuel pump there is a filter element inside there. I replaced my fuel pump trying to solve my problem and the filter element in the old pump looked pretty bad. The replacement pump from Skidim does not have a filter inside.

swb911
09-19-2017, 12:26 AM
That link is old and won't load. I'm curious as to what your fix was.

tex599
09-19-2017, 11:50 AM
Could be several things, I would check your secondaries to make sure they are equal to your primaries when you are having this issue. Might be the accelerator pump, but not likely. Check your timing to make sure it's correct. Might need to go back through carb, but would check fuel pressure first. Most mechanical pumps either work or they don't in my experience.

swb911
09-19-2017, 12:06 PM
Yes, I have checked the obvious and possibly not so obvious.
1) Newly rebuilt carb from MrMastercraft. 4160 set up for my 7.4 liter PCM.
2) New 3/8 hard lines from pump to carb.
3) New mechanical pump.
4) New water/fuel sep. filter.
5) cleaned, then removed the anti siphon valve.
6) New plugs, wires, and new pertronix marine distributor and coil. Timing spot on using SnapOn advance timing light.
7) New hoses from tank to filter and filter to pump.
8) Checked filter screen on carb, clean.
9) confirmed float level is correct.
10) when the issue arrises, I confirm that the carb is out of fuel by manually pumping the accelerator and no gas comes out the squirters. Once I crank over the engine, the carb fills up quickly.

This is the recent accounting of what is going on:
driving at 30mph for an extended period of time, boat started to die so I backed off to about 20mph, went good for a few minuets then started to die some more, then totally died so I waited a couple minutes started it and drove at 20mph before slowing down to dock where it puttered at idle, then Filled up with gas and cruised home at 25mph with no problems. went for a ski 2 hours later at 30mph and boat died mid run, waited a couple minutes before I started it up and it started ok, then today was cruising at 25mph for about 15 minutes before it started to die, slowed down to 15mph where it eventually died moments later, waited and then started again then cruised just above idle for 10 minuets before dying again, started it up and cruised at idle for 15 minutes before dying then that process just repeated 3x before getting to the dock

thatsmrmastercraft
09-19-2017, 12:34 PM
I am wondering if your custom hard lines are not providing enough fuel flow. Did you try running on an external tank as we discussed?

swb911
09-19-2017, 01:24 PM
Possible. I was having this issue before though and I would think that 3/8 hard lines would have a better flowrate than rubber lines. 3/8" lines should provide more than adequate fuel delivery to up to 600hp from what I have read (and the internet is always right). I have not tested the external fuel tank as it has been dumping rain since we talked. Hope to try this week though.
If it fails the external tank test though, and bypassing the water/fuel filter the culprit HAS to be the carb?

pkskier
09-19-2017, 01:47 PM
The rubber fuel line from the tank to the pump has been soften by ethanol & the pump can collapse the fuel line as the RPMS increase. Replace the line.

swb911
09-19-2017, 01:59 PM
Line was replaced... new lines from fitting on top of tank to the pump. The only part that has not been addressed is inside the tank. I tried when replacing the other lines last year to access the pick up in the tank and was unsuccessful. The fitting on top of the plastic tank was far too tight and I feared breaking it...

pkskier
09-19-2017, 07:57 PM
Sorry, didn't do a good job of reading. The fitting at the top of the tank has a spring and ball in it, if there was debris in the tank and could pick it up and clog that fitting so that you are not getting full fuel flow.

swb911
09-19-2017, 08:06 PM
Yes, the ball fitting is the anti siphon valve. This was first cleaned...then removed for testing.

DOes anyone know if there is anything in the tank (like a screen or sock) that could be causing the problem?

Has anyone had success removing the fittings and pick up tube from the plastic tank?

Thank you,

waterlogged882
09-19-2017, 08:42 PM
DOes anyone know if there is anything in the tank (like a screen or sock) that could be causing the problem?

Has anyone had success removing the fittings and pick up tube from the plastic tank?

Thank you,
If I am thinking about the correct year model, yours being an 86, I think there is a screen on the end of a straight pickup tube that is in the fuel cell. I'd have to see a photograph of the assembly to be sure. I took an older model apart just a few months back.

There is a fairly recent thread here about the fittings and someone's mod to a fuel cell to make it work....tutorial with photographs.

Check every hose clamp on the fuel line assembly for tightness.

You can run a straight fitting without a ball / check valve. It won't kill it. I have done several this way. Still working like a Timex.

.

Footin
09-19-2017, 09:50 PM
The pick up screen inside the tank?

waterlogged882
09-19-2017, 10:11 PM
The pick up screen inside the tank?

Yes. The long (pick-up) tube in the photo had a fine-mesh screen attached to the bottom of it.

.

Footin
09-19-2017, 10:17 PM
I had a friend that had this screen clog.

swb911
09-20-2017, 11:14 AM
I had a friend that had this screen clog.

While my tank is plastic, I have a feeling that this is the issue. Has anyone had success removing and inspecting the plastic tank pick up?

I have tried to remove it and was worried i was going to bust up everything. When looking at your photo, I think I may be able to add a bit of heat and a larger wrench...