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Tecumseh - Fuel Starvation

#1

W

wcmans67

Hey all,
I have a Tecumseh 5HP Snowblower engine that is starving for fuel. Starts just fine, idles great and pretty much runs well. After 10-15 minutes it begins to sputter. Turning on the choke and reducing the throttle seems to help but will usually run out of fuel and die out. It's like it is using fuel faster than the gravity supply system can provide fuel to the bowl and eventually starts to starve out and dies. The needle does provide good (but could be better) fuel delivery to the bowl.

Engine model is below and is on an older Toro Powershift 1232. Presented to me with a carb in pieces. Ordered new OEM carb (640105), checked the float bowl after install (drill bit check), replaced fuel line and shutoff & spark plug. Does not have a fuel filter and I also replaced the ignition coil as the insulation was worn through where it comes out of the flywheel cover.

Engine model: OHSK120 222024F (H)

Any help or suggestions are certainly welcome.

Thank you,
Chris


#2

H

hlw49

wcmans67 said:
Hey all,
I have a Tecumseh 5HP Snowblower engine that is starving for fuel. Starts just fine, idles great and pretty much runs well. After 10-15 minutes it begins to sputter. Turning on the choke and reducing the throttle seems to help but will usually run out of fuel and die out. It's like it is using fuel faster than the gravity supply system can provide fuel to the bowl and eventually starts to starve out and dies. The needle does provide good (but could be better) fuel delivery to the bowl.

Engine model is below and is on an older Toro Powershift 1232. Presented to me with a carb in pieces. Ordered new OEM carb (640105), checked the float bowl after install (drill bit check), replaced fuel line and shutoff & spark plug. Does not have a fuel filter and I also replaced the ignition coil as the insulation was worn through where it comes out of the flywheel cover.

Engine model: OHSK120 222024F (H)

Any help or suggestions are certainly welcome.

Thank you,
Chris
Click to expand...





Check fuel tank vent. Take the fuel line loose from the carb and let fuel drain in a good clean container and see it fuel stops draining after a few minutes. If it does fuel cap is not venting.


#3

W

wcmans67

hlw49 said:
Check fuel tank vent. Take the fuel line loose from the carb and let fuel drain in a good clean container and see it fuel stops draining after a few minutes. If it does fuel cap is not venting.
Click to expand...
Thanks hlw49. Will definitely try that!!!

Thank you,
Chris


#4

R

Rivets

Also, check for garbage in the tank, causing the fuel to stop flowing.


#5

W

wcmans67

Gravity feed did not change until the tank was empty and the the tank is clean with no obstructions.


#6

R

Rivets

As soon as the engine starts to sputter disconnect the fuel line from the carb and check the fuel flow. We need to know if the problem is inside or outside the carb. If the the flow is good the problem is in the carb. If the flow is reduced problem outside the carb. You can also check the flow by installing a small clear filter inline to watch the fuel flow. I would also get an inline spark tester to check the spark while running and when the problem starts. We want to rule out a bad coil which is developing a hot short or hot open when it warms up.


#7

C

chutch

I had a similar problem. Some kid had put random items from hardware store in gas tank. The items would sometimes block the fuel intake in the tank


#8

W

wcmans67

Rivets said:
As soon as the engine starts to sputter disconnect the fuel line from the carb and check the fuel flow. We need to know if the problem is inside or outside the carb. If the the flow is good the problem is in the carb. If the flow is reduced problem outside the carb. You can also check the flow by installing a small clear filter inline to watch the fuel flow. I would also get an inline spark tester to check the spark while running and when the problem starts. We want to rule out a bad coil which is developing a hot short or hot open when it warms up.
Click to expand...
Hi Rivets.
Both the carb and the coil are new OEM replacements. Granted it does not mean that either could not have been bad out of the box. That said, the gravity feed is not all that great once disconnected and in the same orientation and does not deteriorate with the old/new/no fuel cap.

The fuel line dips down as it goes down through/behind the flywheel shroud and back up and back into the carb. When it is in the upwards orientation back into the carb, the fuel flow is not that great, BUT if I point it down toward the ground it flows like gang-busters. It's almost like the fuel tank isn't high enough to provide enough gravity back up to the carb inlet.

-Chris


#9

W

wcmans67

chutch said:
I had a similar problem. Some kid had put random items from hardware store in gas tank. The items would sometimes block the fuel intake in the tank
Click to expand...
Thanks Chutch. I have drained, removed the tank and have blown compressed air through.

-Chris


#10

S

STEVES

Hi, the OHSK120 222024F (12hp), have you tried flow without shut off? Seen a couple of bad ones over the years.


#11

Fish

Fish

I would suggest that you adjust your valves.


#12

R

Rivets

Never had a problem with the tank not being high enough on those old mules. Are you sure that you did not pinch the fuel line when you routed it behind the flywheel? Also, if you used fuel line which has a wall thickness which is too large. This will cause the line to pinch together when routed? From your description I’m guessing we’re missing something simple.


#13

M

mmoffitt

chutch said:
I had a similar problem. Some kid had put random items from hardware store in gas tank. The items would sometimes block the fuel intake in the tank
Click to expand...
I was that rotten kid and always wondered who brought that mower. I want to apologize "I'm sorry"


#14

J

Joed756

I would use an in-line spark tester, see what it looks like when you first start and the blower is running well, then, go ahead and use it, if it starts to sputter look at the tester and if the spark seems to have a miss. If so replace your plug, if it still happens replace your coil. Regarding fuel flow from the tank, it doesn't need to be much, trust gravity on that one.


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