Wisconsin VH4D carb/fuel injection swap

Without throttle position and crankshaft sensor and an ECM to control it there's really no way to make this work under an actual load. Unless you have the electronics ability to build and program the ECM you're probably better off just buying a TBI system rather than trying to re-invent the wheel, there's dozens of companies that make them like howell or megasquirt.

Just my input and not trying to push you back to the carb option. And I know nothing about fuel injection. Do you know there are at least 2 different zenith carbs. used on the VH4D, and several others by other manufactures other than zenith? Don't know if that would help with your vapor locking issue.

From looking at your posts on other threads on here it seems like you are fairly knowledgeable on these engines/carbs.

I don't know if you have any of the attached 3 documents. Two reference the zenith carbs (and other brands) used on the VH4D. The third is the VH4D repair manual which shows how to set up the carb. But, I think you know how to set them up already. Maybe someone else may be able to use them sometime.

This is what I have:

Late 70's New Holland/Sperry L325 skid steer with the VH4D engine with a Zenith model L63 carb. Engine was completely rebuilt in the 2000's. I do not have issues with running regular unleaded gas in any temps. We may have different blends than you do especially in the winter. I am from Central PA. I have placed winter and summer blends of 87 octane in this and it runs great with no adjustments needed. There is a 1.5 psi electric fuel pump (which is what this carb is rated for) and an inline filter pushing the fuel through the system. I would need to look at it again, but I think we ran the fuel lines away from the engine. This was more to keep it out of the way when working on it than anything else.

Hope you solve your problem. Looking forward to updates on how the injection system works.

JMV said:

Just my input and not trying to push you back to the carb option. And I know nothing about fuel injection. Do you know there are at least 2 different zenith carbs. used on the VH4D, and several others by other manufactures other than zenith? Don't know if that would help with your vapor locking issue.

From looking at your posts on other threads on here it seems like you are fairly knowledgeable on these engines/carbs.

I don't know if you have any of the attached 3 documents. Two reference the zenith carbs (and other brands) used on the VH4D. The third is the VH4D repair manual which shows how to set up the carb. But, I think you know how to set them up already. Maybe someone else may be able to use them sometime.

This is what I have:

Late 70's New Holland/Sperry L325 skid steer with the VH4D engine with a Zenith model L63 carb. Engine was completely rebuilt in the 2000's. I do not have issues with running regular unleaded gas in any temps. We may have different blends than you do especially in the winter. I am from Central PA. I have placed winter and summer blends of 87 octane in this and it runs great with no adjustments needed. There is a 1.5 psi electric fuel pump (which is what this carb is rated for) and an inline filter pushing the fuel through the system. I would need to look at it again, but I think we ran the fuel lines away from the engine. This was more to keep it out of the way when working on it than anything else.

Hope you solve your problem. Looking forward to updates on how the injection system works.

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To add to that, I always run premium 91 octane no ethanol gasoline in my bobcat 700 with the Wisconsin vh4d engine. It will flood when you shut it off hot sometimes but runs really good otherwise.

Thanks for the replies. Yes, I am aware of the after market fuel injection options on the market. Have any of you found one for a VH4D? I may be wrong, but don't think I'm trying to re-invent the wheel. It's just that no "wheel" has yet been invented for this buggy. I am willing to try adapting a universal maf, oxygen sensor, and tps to work together with a basic computer board, I just haven't found such an animal yet. I have researched the carb models and am aware of the zenith model changes. I have rebuilt both of mine so many times, it's no longer funny…or fun. I'm glad that y'all are enjoying your carburetors and running circles around your 1000 gallon fuel tanks of 91 octane, but I'm on a budget here and also hopeful to help any one else out there crazy as me to try such a mod.

Specifically, I'm hoping that someone is technical enough to help me take a 12v fuel injector, wide band o2 sensor, map, and tps, put them together and make it run. I can see how this would be really helpful in many other applications as well!

Thanks again for the thoughts in this direction.

As previously mentioned, there are companies out there making aftermarket fuel injection systems if that is the direction you wish to go. The system would be sized by engine displacement. Howell systems are based off GM Throttle Body Injection {TBI} units. These systems are reliable as a locomotive and pretty simple in design. Some of the basic requirements these systems need are rpm{crank sensor}, load MAF or MAP sensor}, engine and intake air temp. O2 sensor may not be necessary.
Even Zenith makes{or did} a fuel injection system called ZEEMS, It also was based on GM TBI. I have worked on one of those and can tell you 1st hand I would not recommend it.
My 742B with the Mitsubishi gas motor works great in all temps here in the Boston area. I have had trouble with carburetor needle/seat issues but MANY carb kits are no longer made with alcohol friendly components that can aggravate fuel system problems regardless of how many times parts are changed.
I would be interested in hearing more specifics on the issues you are having with your vapor lock problems.

Hope this is helpful--from what I saw on the aftermarket sites--this one http://www.megamanual.com/v22manual/minj.htm#size One of the necessary steps is to size the injector. My 36 hp 742B seems to use about 2 gal/hr when working. So something on the order of 12 lbs/hr from a single injector. I assume a 30 hp VH4Duses a little less. From the above site: 30hp with 1 injector wants 17.4 lbs/hr. or 126 cc/min--no idea why not consistent with my field derived numbers. Can you run your injector and tester in a container long enough to determine its output? Can you increase the fuel pressure directly via an adjustable fuel regulator, if there is such a thing for whatever pressure you are running? I don't recall you saying, but assume you had to put in a higher pressure fuel pump to get ~ 40 psi? But, no matter what you are going to have to have something ( a computer) that can balance throttle opening as load changes with rpm and hence air volume and fuel mixture. I don't see a satisfactory approach with trying to manually adjust fuel pressure to regulate fuel mixture unless you are doing something with an absolutely steady load, which I doubt you are. So instead, the governor is going to be constantly changing the throttle opening, and rpms are going to be going up and down in response to that and load. So, back to carbs--I dug around a little more. I assume you want 2800 rpm. the VH4D is 107 cu in, or 1753 cc, or 86 cfm @ 2800 It still seems like since you could adapt plumbing parts to do the injector, you could create a new base for a carb up above the exhaust manifold, buy a chinese import for a 1600-2400 cc or so engine (eg 1978 Dodge w/ 4g323 1600 cc Mitsubishi engine), make a governor rod, and be good to go. I did that for my 742B. Carb, ~$100. New gov rod from junk on hand. Base plate from a piece of 1/2" plate, with only one hole in it to match one of the 2 carb barrels, essentially same as Bobcat did originally. Had to trial and error the gov connections to get the needed stroke length, but other wise not a lot of trouble. Runs good, but I think I will want to check for a little too lean (the exhaust smells a lot better than with the original carb). Back to DIY EFI, pattonmachine.com seems to be making EFI retrofits for smaller engines, but you are going to be pushing $2000 before you're done. At least we are keeping this post alive. Hope we aren't irritating.

T-rustyfix said:

Thanks for the replies. Yes, I am aware of the after market fuel injection options on the market. Have any of you found one for a VH4D? I may be wrong, but don't think I'm trying to re-invent the wheel. It's just that no "wheel" has yet been invented for this buggy. I am willing to try adapting a universal maf, oxygen sensor, and tps to work together with a basic computer board, I just haven't found such an animal yet. I have researched the carb models and am aware of the zenith model changes. I have rebuilt both of mine so many times, it's no longer funny…or fun. I'm glad that y'all are enjoying your carburetors and running circles around your 1000 gallon fuel tanks of 91 octane, but I'm on a budget here and also hopeful to help any one else out there crazy as me to try such a mod.

Specifically, I'm hoping that someone is technical enough to help me take a 12v fuel injector, wide band o2 sensor, map, and tps, put them together and make it run. I can see how this would be really helpful in many other applications as well!

Thanks again for the thoughts in this direction.

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There's all kind of euopean 4 cylinder cars that ran Zenith carburetors like MG's that they make complete fuel injection kitsfor if you're determined to fuel inject it. But you could just repower it with with a modern engine for the same money you're going to spend building or buying a vh4d system. I think you best lower cost option would be to call Megasquirt and tell them what you're wanting to do.

Thanks for the advice! I will look into these suggested options and get back with y'all. I have already tried a Chinese carburetor, modified governor linkage, bought 100 jets to play around with, all with similar results. The fuel pressure I am getting is around 120 psi, and I can get 2800rpm with a good mix. It's just that under load, it leans out. As it stands, it runs better now than it did, so any improvement from here are gravy.

T-rustyfix said:

Thanks for the advice! I will look into these suggested options and get back with y'all. I have already tried a Chinese carburetor, modified governor linkage, bought 100 jets to play around with, all with similar results. The fuel pressure I am getting is around 120 psi, and I can get 2800rpm with a good mix. It's just that under load, it leans out. As it stands, it runs better now than it did, so any improvement from here are gravy.

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With the chinese carb you tried, what jet(s) did you find gave you the best for torque mix at full throttle, please, and which jets did you buy to try? And, did you run it as a 2bbl or a 1 bbl by blocking/disconnecting the 2ndary? Thank you

Dave1234 said:

With the chinese carb you tried, what jet(s) did you find gave you the best for torque mix at full throttle, please, and which jets did you buy to try? And, did you run it as a 2bbl or a 1 bbl by blocking/disconnecting the 2ndary? Thank you

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I tried a PWK24 off Amazon with a 52 mm aluminum tube fit into the carb intake. The main jet size was 120. I attached the throttle cable to the governor linkage but it still wouldn't open enough to keep her from leaning out under a load. What is your project? Perhaps I could help you figure something out.

T-rustyfix said:

I tried a PWK24 off Amazon with a 52 mm aluminum tube fit into the carb intake. The main jet size was 120. I attached the throttle cable to the governor linkage but it still wouldn't open enough to keep her from leaning out under a load. What is your project? Perhaps I could help you figure something out.

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Amazon shows that carb for a 196 cc engine--I doubt it could ever supply adequate fuel to your 1700 cc Wisconsin motor. Might be worth taking another run at a larger carb. I used this from Amazon: Carburetor 6632616 Compatible with Bobcat Skid Steers Loaders 642B 742B Mitsubishi 4G32 engine. My problem was a carb that suddenly started running very rich, but that had always smelled too rich anyway. Couldn't find specs for float height anywhere. Carb otherwise was good, but I tried and didn't like shooting in the dark on float height. So tried the above. Wasn't a simple swap, but not too complicated for my 4g332 engine, 1600 cc. There are endless vendors selling apparently identical carbs. This is a 2 bbl carb, similar to the original, where Bobcat had blocked off the secondary throat, so I did too. I assume it was sized for 1600 cc at ~ 5-6000 RPM, not 2800. I would like to be able to measure the mixture richness to make sure I am not too lean--I suspect these carbs are made for fuel economy in a car, not max torque in a bobcat, so likely the main jet is a little small, but just a guess at this point. What did you buy to measure your fuel richness with? And how did you know what size jets to try in terms of threads and overall dimensions? Having no way of knowing anything about the carb I now have is a worry--I will never be able to buy a carb kit for it, nor know float height. I think it is basically disposable for $100. I will never put enough hours on it to matter if it is of reasonable quality. It seems to be.

I bought these carbs off Amazon. My Wisconsin runs great with it. Can't remember which out of the 2 I actually used. Only a few mods for the throttle linkage

I installed an oxygen sensor and afr gauge to ensure proper mix.

Dave1234 said:

Amazon shows that carb for a 196 cc engine--I doubt it could ever supply adequate fuel to your 1700 cc Wisconsin motor. Might be worth taking another run at a larger carb. I used this from Amazon: Carburetor 6632616 Compatible with Bobcat Skid Steers Loaders 642B 742B Mitsubishi 4G32 engine. My problem was a carb that suddenly started running very rich, but that had always smelled too rich anyway. Couldn't find specs for float height anywhere. Carb otherwise was good, but I tried and didn't like shooting in the dark on float height. So tried the above. Wasn't a simple swap, but not too complicated for my 4g332 engine, 1600 cc. There are endless vendors selling apparently identical carbs. This is a 2 bbl carb, similar to the original, where Bobcat had blocked off the secondary throat, so I did too. I assume it was sized for 1600 cc at ~ 5-6000 RPM, not 2800. I would like to be able to measure the mixture richness to make sure I am not too lean--I suspect these carbs are made for fuel economy in a car, not max torque in a bobcat, so likely the main jet is a little small, but just a guess at this point. What did you buy to measure your fuel richness with? And how did you know what size jets to try in terms of threads and overall dimensions? Having no way of knowing anything about the carb I now have is a worry--I will never be able to buy a carb kit for it, nor know float height. I think it is basically disposable for $100. I will never put enough hours on it to matter if it is of reasonable quality. It seems to be.

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I installed this for fuel ratio confirmation. It works great and gives real time afr data.

T-rustyfix said:

I installed an oxygen sensor and afr gauge to ensure proper mix.

I installed this for fuel ratio confirmation. It works great and gives real time afr data.

Amazon.com

a.co

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Thank you!