Bubbles in my fuel line

Welcome to our Community
Wanting to join the rest of our members? Feel free to sign up today.
Sign up
Feb 20, 2018
5
0
1
Real Name
David Hoon
#1
My engine cuts out after being on for about 20 minutes...when I turn the heat on. I have to wait for it to cool a few minutes before it will start again. I look at the clear fuel filter on the side of the engine and there's bubbles coming up from it. I turn the heat off and wait a few..then it restarts. If I'm not pumping the water thru my wand every once in a while then I think it gets too hot. :-(

45 blower
CAT pump 3.6 GPM

I have a Kohler CH23S. I bought my whole van with TM used. There's an electronic fuel pump (5.5 - 9 PSI) along with a metal fuel filter right before it(can't see inside it) under my van and the fuel line comes up through the van floor. TM engine draws fuel from my van's tank. I installed Mr. Gasket fuel regulator to bring the pressure down around 1.5 to 2 PSI. I was told this engine is rated to receive this pressure. After the regulator, it goes to a clear plastic fuel filter, then straight to the carb. I can see bubbles coming up into the clear fuel filter when the engine is running. Anyone know what the problem could be?

Not sure if it was bubbling before I put on Mr Gasket regulator or not. After TM running for a bit the Mr Gasket gets a bit hot. Is the fuel hot already coming from the fuel pump? ..or is it possible the fuel is warming BECAUSE of the Mr Gasket regulator? I need a regulator..but I can always put a different one on if this one I got is garbage.

The Mr Gasket is about 3 inches from the motor..however, the clear fuel filter is even closer..like touching up against the engine itself..but near the top. I don't think I've ever seen bubbles in the clear filter before installing Mr Gasket.

What I'm going to try:

1. Wrapping the Mr Gasket in some heat resistant tape. Maybe keeping it cool might prevent bubbles. I donno.
2. Put Mr Gasket further from the motor all together if the tape doesn't work
3. Change the metal fuel filter (the one under the van, just before the fuel pump) Don't know when it was changed last.
4. Rerouting the fuel line around the engine & exchanger instead of right under it. Fuel line is on the van floor and the bottom of the heat exchanger is about 3 inches above it. Do you think the fuel could heat up THAT much (in a rubber hose) just traveling fast under the exchanger?
5. ??? Anything else I can try?

Can bubbles form from just the line and fuel being heated? ..or does there need to be air in the system already for this to happen?
Does there HAVE to be some sort of leak in my fuel line in order for air bubbles to get in?

The end of the fuel line just dumps into an open carb so donno how much air travels back down the fuel line.

When the engine is off the fuel in the clear filter is gone. I guess it's gone down below it.

That's about all I have right now.

Thanks for any help.
 

Todd the Cleaner

Todd Cottino
Staff member
Administrator
Moderator
Premium VIP
Sep 4, 2011
22,196
13,907
113
47
Pahrump, Nevada, United States
www.toddscleaningservice.com
Real Name
Todd Cottino
Business Location
United States
#2
If you are seeing bubbles in the fuel then it’s sucking air in. I would be looking at the hose between the fuel tap and the fuel pump, there must be a lose hose clamp or a pinhole leak in the hose. If the problem was after the fuel pump you would see fuel leaking.

You might want to just replace the whole fuel pump, get a 2-5 psi pump and you can get rid of the regulator. I’d pick up new fuel hose while you are at it and replace the rubber fuel hoses on both sides of the pump.

Here’s the pump I use.
https://m.autozone.com/fuel-systems...fuel-pump-for-fi-applications/349165_0_0?aqs=


BC316B11-4224-4D24-BF57-C2DF8B81D279.png
 
Feb 20, 2018
5
0
1
Real Name
David Hoon
#3
Thanks for your help. It may vary well be leaking fuel. Test for a leak or simply replace the entire hose?

Could that metal fuel filter be clogged or bad? or do you truly believe there is a hole somewhere?

My engine needs 1.5 to 2 PSI ...you think ok to put that one on? It can be set at 2 PSI permenantly?
 

Todd the Cleaner

Todd Cottino
Staff member
Administrator
Moderator
Premium VIP
Sep 4, 2011
22,196
13,907
113
47
Pahrump, Nevada, United States
www.toddscleaningservice.com
Real Name
Todd Cottino
Business Location
United States
#4
I’ve been using those pumps for years on both my kohler and Honda engines. I’ve never used a fuel regulator. I’d try it without the regulator but keep the regulator just in case.

As cheap as fuel hose is I’d just go buy 10 feet of it and replace all your fuel hoses. It’s good to replace the hoses every few years anyway.
 

Todd the Cleaner

Todd Cottino
Staff member
Administrator
Moderator
Premium VIP
Sep 4, 2011
22,196
13,907
113
47
Pahrump, Nevada, United States
www.toddscleaningservice.com
Real Name
Todd Cottino
Business Location
United States
#5
Could that metal fuel filter be clogged or bad? or do you truly believe there is a hole somewhere?
There has to be a leak somewhere for air to be getting into the line. It’s possible even the pump itself is going bad but I’m guessing it’s a bad hose between the fuel tap and fuel pump.
 

Kevin Dumas

Well-Known Member
Aug 31, 2008
3,012
626
113
Binghamton, NY
Real Name
Kevin Dumas
#6
I run Mr. Gasket fuel pumps (2-3.5) psi and no regulator needed for your engine.
I would replace the pump, fuel line and filter placing them away from the engine as far as possible.
This should eliminate any fuel delivery problems unless your pickup hose inside the tank is bad and drawing air.

Please explain further about when you turn on the heat and the engine dies.
What kind of heat?
 
Feb 20, 2018
5
0
1
Real Name
David Hoon
#7
Thanks for all of your help.

I was going to replace my fuel pump with the Airtex E8016S Universal Electric Fuel Pump 2.5 to 4 PSI one. Only $32.


Let me know if you think this will work. Thanks.

p.s. I checked the fuel line all the way to the mr gasket and I don't see any leaks at all.