VST, high RPM bogging, fuel issues, etc, all in one thread

[rangerdog]

Like a lot of folks, I too have run afoul of the "shuts down at high rpms gremlin." Now will idle for a while then the bulb gets soft and then she shuts down I must pump up the bulb. Here's what I have done.

Because I needed to check and clean the vst anyway I started with the VST. Very clean, only about four of the pin holes were clogged; the float and pan were immaculate. I assume the injecters are as well. Changed the "F" filter, changed the on motor water filter, put on a new bulb, put on a new blue 10 micron filter. The next thing (working back) I will pull the fuel line from the tank and check for clogs at the pick up tube. (and the rest of the fuel line) I checked the fill cap for vapor lock that way and the air inlet seems fine.
Hopefully, there will be a fouled screen on the pick up tube in the tank, if not, I may be out of ideas. Although I guess after checking the tank I should check both fuel punps for proper operation, but they do not leak and passed the "blow in the little tube test" when they were off. Any other ideas? I am trying to troubleshoot this upstream and logically.

 

[itguy]

I do not know what engine or boat you have, so this may not be an appropriate solution. I had a similar problem with my 2120 SC with a 200 4-stroke Yammi. The tank was fine, but the anti-siphon valve at the tank was all clogged. This led to the engine dying at high speeds with the bulb showing full compression. Replacing the valve with a new Moeller solved the problem. The dealer gave me a different ASV (that was not a Moeller) and it DIDN'T work! Be sure and get a Moeller. The spring must have the correct compression or it will not let the gas flow correctly to the engine. You can test this out ahead of time by getting a straight thru connector that does not have any anti-syphon capability. If everything works, you know that was the problem. Just be sure and replace with the new anti-syphon valve.

Itguy

 

[Brent]

You may not need an ASV on the fuel tank if the fuel line is higher than the fuel tank in the overall run to the motor
ex fuel line goes to Racor fuel and water filter mounted in the stern and is higher than the fuel tank.

If you pull the fuel pickup tube, check the length. Maybe the tank is 24'" inches deep and someone changed it earlier and used a 20" long tube. I replaced mine using a nylon tube and the end didnt have a screen or the elbow, and the tube was cut on a bevel

 

[Brent]

Did you check the fuel tank vent hose and vent?

 

[rangerdog]

I do not know what engine or boat you have, so this may not be an appropriate solution. I had a similar problem with my 2120 SC with a 200 4-stroke Yammi. The tank was fine, but the anti-siphon valve at the tank was all clogged. This led to the engine dying at high speeds with the bulb showing full compression. Replacing the valve with a new Moeller solved the problem. The dealer gave me a different ASV (that was not a Moeller) and it DIDN'T work! Be sure and get a Moeller. The spring must have the correct compression or it will not let the gas flow correctly to the engine. You can test this out ahead of time by getting a straight thru connector that does not have any anti-syphon capability. If everything works, you know that was the problem. Just be sure and replace with the new anti-syphon valve.

Itguy

2003 2320DVSC. Four Stroke F225. I don't know if I have an ASV or not, I guess I will find out this afternoon. GREAT tip. No one has mentioned this yet. That's why I wanted to get all this information on one thread.

Might save you some trouble. There was/is no screen on fuel pick up tube ('03 23DVCC). My tank has 2 complete p/u's. You might try switchin to other p/u w/temporary fuel line to second fuel filter inlet (way easier than trying to move existing fuel line). Un-used side doesn't have anti-siphon valve.

Did yer "F" filter have spring clips or some sort of metal bands crimped into place ?
Do I need to relieve pressure (if any) on hoses at "F" filter before changing

I assume this is for a two engine set up? Humm. I'll check if I have this or not. Again no one has ever mentioned this possibility, another great tip.

"F" filter had spring clips, By bthe time I got to it there was no fuel to have pressured up as I had already unhooked the engine mounted water filter.

You may not need an ASV on the fuel tank if the fuel line is higher than the fuel tank in the overall run to the motor
ex fuel line goes to Racor fuel and water filter mounted in the stern and is higher than the fuel tank.

If you pull the fuel pickup tube, check the length. Maybe the tank is 24'" inches deep and someone changed it earlier and used a 20" long tube. I replaced mine using a nylon tube and the end didnt have a screen or the elbow, and the tube was cut on a bevel

I'll check but I bought the boat with only a few hours on her.

Did you check the fuel tank vent hose and vent?

It is certainly on my list to do. Mud-daubers are all over the place!

 

[KETABUG0]

IT SOUNDS LIKE YOU HAVE A CRACKED GASKET IN ONE OF YOUR FUEL PUMPS. PULL THE PUMPS AND CHECK THE GASKETS.

 

[Megabyte]

I have nothing to add, but I'm tagging this thread to learn good information.

 

[Parker23]

Low pressure pumps.

 

[Parkerman]

Sounds all too farmiliar. I ended up sending my injectors on a vacation at a spa in Florida to be cleaned.

 

[Striperswiper]

I had a similar problem with a used Parker I bought.

Turns out the previous owner let 3 of the little metal seals on the fuel stabilizer additive bottles fall into the fuel tank.

I'd be crusing along and the metal seal would get sucked onto the intake pipe in the tank and shut me down. Then fall off and everything would be good until it did it again.

I ran it almost out of fuel then took the fuel gauge sender out and looked in the tank. Got them out with one of those spring loaded claws you use for retreiving stuff you drop in an engine and can't get with your hand.

 

[rangerdog]

OK here's the fix for my boat. Checked the fuel filler and vent. All clear. Removed the pick up tube, all clear. Checked the Anti Siphon Valve. It was bad. I have ordered another but I ripped out the spring and valve and put it back together. The boat purrs like a kitten and revs like a Jaguar. I also decided to test the low pressure fuel pump se I pulled it bench tested it and it works great. Buttoned it all up and saw that there is a pretty Good leak from the port trim piston. So now I need to order the piston kit from SIM and wait for it to come in and hope I can get her out on the water this weekend. That's for another thread.

So:

Boat acting bad won't run at higher RPMs fuel misses at idle.

Checked VST-VST spotless cleaned filter (needed done anyway)
Checked engine mounted water filter-cleaned (needed done anyway)
Checked F filter-cleaned (needed done anyway)
Replaced 10 Micron filter (needed done anyway)
Checked all fuel hoses, replaced bulb (needed done anyway)
Checked ASV, modified ASV, problem fixed.

Lesson learned: Do the ASV before anything. It is an easy fix (if that's the problem) before tearing into VSTs or replacing $500 fuel pumps.

John

 

[itguy]

I'm not at all suprised the ASV was clogged - that's what happended to me. You can pick one up at West Marine. Make sure it is a Moeller!!!

Itguy

 

[rangerdog]

How did you determine the ASV was bad ?

How did you "rip" the spring and valve out ? My spring and "valve" (a ss ball) were held in place by a "shoulder" something like an inside "flare"....had to drill it out.

Well I blew through and it was hard to do. Then somewhere I found a pressure test/spec that had me put a clear tube on the "tank" side and fill it with 24" of water. The water should flow out as you add more than that (about 26") Anyway everyone in the family blew through it and deemed it faulty. Valve removal: ASV in large vise. Steel punch in ASV. One whack with a 9 pound sledge, no more innards! 8)

 

[Brent]

When I replaced the ASV, I drilled out the stop and spring and ball were removed. On my setup I didnt see the need for ASV since the fuel line goes higher than the tank at the stern then down to the RACOR fuel and water filter then out to the motor. Next year, I will add a on/off valve on the filter head for safety

 

[Parker23]

Sometimes debri gunks it up and causes a restriction of fuel, who knows. Mine took a poop after about 2 yrs, i just got rid of it all together