Blowby

[John2189 454]

Would a lot of blowby stop the impulse fuel pump from working?

[ebinmaine 67,658]

By pure logic I could see that being an issue but a lot of the vacuum pulse pumps require only a small amount of change. 

 

What's the engine? 

Aftermarket pump?

 

Can you test it by rerouting the fuel to a canister? 

 

 

[John2189 454]

Its a ch20 kohler   Original  pump. When it stops running, the fuel filter is dry. Normally it is about half full 

i took the hose going to carb and it does spurt a little fuel 

[ebinmaine 67,658]

Does this happen when the fuel tank cap is OFF? 

 

I'm wondering if you have a venting issue? 

 

What's the age of the fuel lines?

 

Has the tractor been run on ethanol gas? 

 

 

[John2189 454]

Cap doesn’t matter 

original hoses from 1996

yes ethanol with stable 360

[ebinmaine 67,658]

4 hours ago, John2189 said:

hose going to carb and it does spurt a little fuel 

 

I can't honestly say I know enough about a CH to comment there. 

A little may be enough... or not. 

 

 

10 minutes ago, John2189 said:

 

original hoses from 1996

 

These NEED replacement by now. 

 

10 minutes ago, John2189 said:

yes ethanol with stable 360

 

There are no known chemicals that reduce the damage done by ethanol to the rubber hoses. 

 

Your original 28 year old fuel lines are just not able to withstand the degradation caused by alcohol in the gasoline. 

 

 

An old saying I learned years ago. 

You can't do proper diagnostics until ALL maintenance is done. 

 

We're at a point where our machines need to be properly maintained repaired and retrofitted to using systems that can better resist the negative effects of ethanol. 

 

Is your pump bad? Maybe. 

 

Your fuel hoses could be cracked just enough that they're allowing air IN but not yet letting fuel OUT. 

 

 

[adsm08 2,080]

29 minutes ago, ebinmaine said:

 

. 

 

 

An old saying I learned years ago. 

You can't do proper diagnostics until ALL maintenance is done. 

 

 

 

 

 

Add to that, "If you didn't do it yourself assume it was done wrong".

 

Although I've worked with a few guys over the years who should also assume it was done wrong if they did do it themselves.

[oliver2-44 9,761]

2 hours ago, John2189 said:

Cap doesn’t matter 

The vent hole in the cap must be open. If it’s plugged as the pump sucks fuel out of the tank, it gets harder and harder for the pump due to a vacuum forming in the tank. 
That’s why it’s recommended to loose or remove the tank cap and see if this improves fuel pump flow. 
Its also easier to check the simple  free things before throwing money at parts. 

Edited July 27 by oliver2-44

[John2189 454]

1 hour ago, oliver2-44 said:

The vent hole in the cap must be open. If it’s plugged as the pump sucks fuel out of the tank, it gets harder and harder for the pump due to a vacuum forming in the tank. 
That’s why it’s recommended to loose or remove the tank cap and see if this improves fuel pump flow. 
Its also easier to check the simple  free things before throwing money at parts. 

I meant if you take the cap off it doesn’t matter or make any difference 

[John2189 454]

If the rings were worn enough to cause blowby, wouldn’t it smoke?  
It doesn’t smoke at all 

[ebinmaine 67,658]

33 minutes ago, John2189 said:

If the rings were worn enough to cause blowby, wouldn’t it smoke?  
It doesn’t smoke at all 

 

Most of the time yes. But that's not a guarantee.

 

It's likely that if you could have the exhaust tested with emissions gases equipment like some states use, you would find excessive levels of certain compounds even though it may not be visible to the eye in most lighting.

[wallfish 17,014]

A vacuum pulse pump requires a flexible diaphragm inside of it in order to pulse from the difference in case pressure. That pulse is what pumps fuel through the check valves.

An original pump with years of fuel (and especially ethanol) will most likely have a stiff diaphragm. Eventually it becomes stiff enough to resist the case pressure so it doesn't pulse, or pulse enough to pump fuel. The check valves inside also get dirty and don't seal as well. When the check valves don't seal the fuel will simply move back and forth inside the lines instead of only being able to move a single direction. (towards the carb) I'm not familiar with those particular pumps but they all work on the same principles. Most of those old pumps you can open up. Clean and inspect. Some you can change the diaphragm, some it's easier to just replace. 

[Wild Bill 633 846]

FYI, if the pump is an early Mukuni DF 52-135 aluminum body pump, you can use rebuild kit, Parts Unlimited/Vertex P/N 451454 or Winderosa 12-1133.

[John2189 454]

Thanks. It runs about an hour then runs out of gas 

[ebinmaine 67,658]

18 minutes ago, John2189 said:

Thanks. It runs about an hour then runs out of gas 

 

 

If it runs for an hour then it's highly unlikely the fuel pump is bad

[wallfish 17,014]

17 minutes ago, John2189 said:

Thanks. It runs about an hour then runs out of gas 

That seems more like the clogged cap vent, a clogging tank filter screen, collapsing fuel line type stuff.

[John2189 454]

1 hour ago, wallfish said:

That seems more like the clogged cap vent, a clogging tank filter screen, collapsing fuel line type stuff.

When it stops running, the fuel filter is completely empty. When running good, the fuel filter is about 1/2 full 

[ebinmaine 67,658]

1 hour ago, John2189 said:

When it stops running, the fuel filter is completely empty. When running good, the fuel filter is about 1/2 full 

 

 

When it stops running does the fuel filter refill immediately? Or does it take a few minutes?

 

 

If it was to stop running and you immediately got off the tractor and opened the fuel tank does the fuel filter refill quickly?

 

 

[John2189 454]

1 hour ago, ebinmaine said:

 

 

When it stops running does the fuel filter refill immediately? Or does it take a few minutes?

 

 

If it was to stop running and you immediately got off the tractor and opened the fuel tank does the fuel filter refill quickly?

 

 

No it has to cool down a bit, then i have to use the choke to keep it running for 20-30 seconds 

[ebinmaine 67,658]

 

I'd say you really need to do the maintenance on that machine and then repeat the test. If your gas cap is near three decades old and your fuel lines are the same, they're just no good. Like it or not..... They need to be replaced.

 

 

 

[John2189 454]

1 hour ago, ebinmaine said:

 

I'd say you really need to do the maintenance on that machine and then repeat the test. If your gas cap is near three decades old and your fuel lines are the same, they're just no good. Like it or not..... They need to be replaced.

 

 

 

I will get new hoses and change them. 

[John2189 454]

18 hours ago, John2189 said:

I will get new hoses and change them. 

Ok put new hoses on. Cap vent is open and it still does it.

I have a pump rebuild kit ordered

[oliver2-44 9,761]

When you had the hose off the tank, did you check for good flow at the tank valve.

If it were me I would replace the tank valve along with the pump kit your installing. that way you know the entire fuel system is in good condition. 

[John2189 454]

5 minutes ago, oliver2-44 said:

When you had the hose off the tank, did you check for good flow at the tank valve.

If it were me I would replace the tank valve along with the pump kit your installing. that way you know the entire fuel system is in good condition. 

Yes full flow out of the tank