1872 hard to start

[PACub100]

Figured I'd get a good answer here before I tried my luck at the world wide web...

What Walbro carb is on my Cub?
I bought a rebuild kit back in the summer before I knew it had a walbro, so basically I just cleaned it up good and put it back together. Seemed to be ok for the time but now, if I don't shut off the gas, I get it in my oil.

When I try starting it, it'll backfire and reek of gas. It won't start today no matter what I do (it's 24⁰ and windy)...

Want to order the correct rebuild kit for it to get me through winter. After that I'm planning on replacing it with the Carter.

 

[mpatterson]

Its the float pin that is allowing gas to flood the engine or something. Think it was Matt G who explained it in a post to me a while ago? I can't remember correctly. It does it to all my tractors if I don't shut off the gas now. There is enough pressure to push the gas down as the tank is higher up in the tractor. I installed the on/off 1/4 turn inline shut off taps in my fuel lines now. Its frustrating as heck when you want to use it and you have an engine full of fuel and oil.
I feel your pain!!!

 

[MarcHeld]

You know, you are getting plenty of gas - it could be a bad coil. Check the ohms on the primaries. Unfortunately it’s an engine-out repair.

 

[tkhoffman]

It's hard to start because it is wicked flooded. It's absolutely the needle valve that is not seating properly. Or the rubber tip on the needle is dried and distorted.
Let me back up a bit. When you had the carb apart, this summer, did you make sure the Float would float? Did you shake it to make sure it didng have gas in it? Did it pivot nice and smoothly when you put it on the Carb with the float pin? If these three question have the answer of "yes" then i would take the needle valve to a decent auto parts store and match it up with a new one. A whole rebuild kit is not necessary. On all my equipment, i add an inline shutoff valve, and use it. Rubber tipped needle valves dry out and get stiff with our harmful, useless alcohol gas.

 

[mgonitzke]

The seat is not included in the carb kit for those Walbro carbs. I'm not sure if it is available separately. Just replacing the needle with the new one in the kit might not have been enough to seal it. I would add a shutoff in an accessible spot right before the fuel pump and use that for now. This will not help if the float went bad and sank though- even when running the tractor will be drowning.

Does the tractor still have the OEM mechanical fuel pump? If so, that can also fail in a way that fills the crankcase with gas. The surefire fix is would be to add a Facet 40177 electric pump and replace the carb with a KT-17 series I carb, or a #26 carb from a K301 with the throttle and choke shafts from the Walbro. I wouldn't wait. If you want to be able to depend on this over the winter, I'd fix it now. Walbro rebuild kit is ~$50 IIRC and may not even fix the issue.

You know, you are getting plenty of gas - it could be a bad coil. Check the ohms on the primaries. Unfortunately it’s an engine-out repair.

Not "plenty"- "too much". He says it smells like gas when cranking. It is flooding. Let's not go off in the weeds here...

 

[tkhoffman]

Figured I'd get a good answer here before I tried my luck at the world wide web...

What Walbro carb is on my Cub?
I bought a rebuild kit back in the summer before I knew it had a walbro, so basically I just cleaned it up good and put it back together. Seemed to be ok for the time but now, if I don't shut off the gas, I get it in my oil.

When I try starting it, it'll backfire and reek of gas. It won't start today no matter what I do (it's 24⁰ and windy)...

Want to order the correct rebuild kit for it to get me through winter. After that I'm planning on replacing it with the Carter.

The seat is not included in the carb kit for those Walbro carbs. I'm not sure if it is available separately. Just replacing the needle with the new one in the kit might not have been enough to seal it. I would add a shutoff in an accessible spot right before the fuel pump and use that for now. This will not help if the float went bad and sank though- even when running the tractor will be drowning.

Does the tractor still have the OEM mechanical fuel pump? If so, that can also fail in a way that fills the crankcase with gas. The surefire fix is would be to add a Facet 40177 electric pump and replace the carb with a KT-17 series I carb, or a #26 carb from a K301 with the throttle and choke shafts from the Walbro. I wouldn't wait. If you want to be able to depend on this over the winter, I'd fix it now. Walbro rebuild kit is ~$50 IIRC and may not even fix the issue.



Not "plenty"- "too much". He says it smells like gas when cranking. It is flooding. Let's not go off in the weeds here...

Hes getting gas in his oil IF he doesnt use his, already installed, Shutoff.
P.S. i have a used , still on my old enhine, carb on my series 1 KT-17. free for the price of shipping.

 

[PACub100]

It's hard to start because it is wicked flooded. It's absolutely the needle valve that is not seating properly. Or the rubber tip on the needle is dried and distorted.
Let me back up a bit. When you had the carb apart, this summer, did you make sure the Float would float? Did you shake it to make sure it didng have gas in it? Did it pivot nice and smoothly when you put it on the Carb with the float pin? If these three question have the answer of "yes" then i would take the needle valve to a decent auto parts store and match it up with a new one. A whole rebuild kit is not necessary. On all my equipment, i add an inline shutoff valve, and use it. Rubber tipped needle valves dry out and get stiff with our harmful, useless alcohol gas.

Yes, the float is good and moves easily.
I never thought about checking with an auto parts store for a needle, perhaps I might get lucky and find a comparable seat...

The seat is not included in the carb kit for those Walbro carbs. I'm not sure if it is available separately. Just replacing the needle with the new one in the kit might not have been enough to seal it. I would add a shutoff in an accessible spot right before the fuel pump and use that for now. This will not help if the float went bad and sank though- even when running the tractor will be drowning.

Does the tractor still have the OEM mechanical fuel pump? If so, that can also fail in a way that fills the crankcase with gas. The surefire fix is would be to add a Facet 40177 electric pump and replace the carb with a KT-17 series I carb, or a #26 carb from a K301 with the throttle and choke shafts from the Walbro. I wouldn't wait. If you want to be able to depend on this over the winter, I'd fix it now. Walbro rebuild kit is ~$50 IIRC and may not even fix the issue.



Not "plenty"- "too much". He says it smells like gas when cranking. It is flooding. Let's not go off in the weeds here...

Well, I ordered a rebuild kit last night... I didn't think about the seat and never bothered to check.

Yes, I'm planning on the facet pump you'd suggested in my other post regarding my brother's 782. In fact,him and I are both going through the same thing so we're doing it together. For the time being, my brother just bypassed his pump, just making sure to keep his tank full enough to work off gravity, I might do the same until it warms up enough to spend a day doing all the maintenance.


It's a good thing I haven't sold my 1450 yet, as it's getting the QA-42A put on today.

 

[tkhoffman]

Yes, the float is good and moves easily.
I never thought about checking with an auto parts store for a needle, perhaps I might get lucky and find a comparable seat...


Well, I ordered a rebuild kit last night... I didn't think about the seat and never bothered to check.

Yes, I'm planning on the facet pump you'd suggested in my other post regarding my brother's 782. In fact,him and I are both going through the same thing so we're doing it together. For the time being, my brother just bypassed his pump, just making sure to keep his tank full enough to work off gravity, I might do the same until it warms up enough to spend a day doing all the maintenance.


It's a good thing I haven't sold my 1450 yet, as it's getting the QA-42A put on today.

If you bro is interested in my carb and/or coil off my retired KT-17..... the engine is sittingbunder plastic to my wifes dismay. I hate to just toss out good old parts.
The coil is an aftermarket Harley Davidson. Its been much more reliable than Kohler OEM.
https://www.ihcubcadet.com/threads/free-k17-complete-leaks-old-but-runs.12591/

 

[Gary M]

My 2072 was doing the same thing, I bypassed the fuel pump and did gravity feed to carb! I used an inline shutoff valve to connect the 2 hoses real easy! Later I discover the fuel pump on the top up motor was loose, not sure how it works or if that could have been the problem!! I’ve been using gravity feed for a few years now, works fine but gas tank level has to be above half!!

 

[Daniel Perry]

The seat is not included in the carb kit for those Walbro carbs. I'm not sure if it is available separately. Just replacing the needle with the new one in the kit might not have been enough to seal it. I would add a shutoff in an accessible spot right before the fuel pump and use that for now. This will not help if the float went bad and sank though- even when running the tractor will be drowning.

Does the tractor still have the OEM mechanical fuel pump? If so, that can also fail in a way that fills the crankcase with gas. The surefire fix is would be to add a Facet 40177 electric pump and replace the carb with a KT-17 series I carb, or a #26 carb from a K301 with the throttle and choke shafts from the Walbro. I wouldn't wait. If you want to be able to depend on this over the winter, I'd fix it now. Walbro rebuild kit is ~$50 IIRC and may not even fix the issue.



Not "plenty"- "too much". He says it smells like gas when cranking. It is flooding. Let's not go off in the weeds here...

Can you send me links or?? On where to find the carbs you mentioned in your comment please. I'm facing similar problems with my 2072 and want to fix it once and correctly. I haven't been passing gas into the oil yet, but it floods if I dont shut the line valve immediately when I shut the engine off.

 

[PACub100]

Can you send me links or?? On where to find the carbs you mentioned in your comment please. I'm facing similar problems with my 2072 and want to fix it once and correctly. I haven't been passing gas into the oil yet, but it floods if I dont shut the line valve immediately when I shut the engine off.

My brother and I each ordered this one...I'm planning on cleaning up the seat with a pipe cleaner or small brass wire brush (depending on severity)

https://www.ebay.com/itm/121148622171