My slightly nicer but also terrible Bobcat (742B)

[Scott Cee AKA 2drx4]

I needed to figure out something for radiator mounting as you couldn't bolt it in the way that Bobcat shows. I'm not sure if the parts manual is missing info, this is the wrong radiator, or if they literally did just bolt it in so it was loaded up from the factory (and then surprise, surprise, it splits the seams).

I made some dowels that will screw into it. This somewhat worked:

Then I put some grommets on them for isolation and spacing:

To hold the fan shroud in place I put some countersunk screws through from the top:

This somewhat worked. I had to cut the dowels down more, it's really tight to get it in, and then I wound up swapping the dowels on the back (machine back) side for bolts and just put extra grommets on them. Overall I still don't know how this would have ever worked from the factory, and I can see why they decided to just not bolt it in instead. But then it chafed on everything. I don't know, not a perfect solution but it will work. This radiator is bent so badly that it is about 3/4" out of flat from one side to the other.

[Scott Cee AKA 2drx4]

The other thing that was missing (and needed) was something to hold the fuel and hydro oil tanks. It also holds the wiring in place, which was probably why it was more important than anything else. This is supposed to be a metal strap, like a gas tank would use, and it's NLA. I didn't feel like bending one up and opted to do something hack, so I made some little brackets and just tied a piece of ratchet strap across. They'd stripped the threads out of the one side of the machine, so I wound up putting some allthread through it to the other side, this made for a hack adjuster for tension. As it was I just tightened the shiiit out of the strap anyway. It's secure. I can fix it right some other time, but nothing is as permanent as a temporary fix.

[Scott Cee AKA 2drx4]

Oh yeah, I hooked up the wires for the fuel sender, and oddly enough the fuel gauge seems to work. Weird. So much stuff on this machine was just left half together.

Anywho, after some tidying things up, adding a battery hold down (just all thread and one of those generic holders from Crappy Tire), and lots of messing around with ignition timing and swapping the coil, I got it to run.

The float height in the carb is wrong, so it won't idle, or maybe there is other things wrong with the carb, but I'm going to start with trying to set the float height correctly. I also think I'm out a tooth on the distributor, because I have a bit more advance than the book calls for and can't adjust it enough. The temperature gauge doesn't work, which isn't ideal given the potential overheating issues on a fresh build. Last thing is a bit disconcerting, but I couldn't get the hydro oil pressure light to go off. The machine moves fine and everything, so I'm not sure if there's a wiring problem (there shouldn't be, I didn't change anything related to those wires) or one of the pressure switches failed.

Anyway, light at the end of the tunnel. Hopefully not an approaching train.

[Scott Cee AKA 2drx4]

This carb is garbage, or I'm just stupid. Took it off to adjust the float height and realized the intake was full of fuel, so it had been leaking into the intake. Oil still smelled fine and hadn't noticeably risen in height, so figured that it's probably not contaminated. It also was leaking out of the split line at the top, again because the float height is wrong or... but it shouldn't leak there either way.

I took the top off and realized it wasn't flat. I didn't check that when I rebuilt it, because why wouldn't it be. So I spent a bunch of time cleaning it up with some stones. I also checked the float height and tweaked the float. The needle leaked, so I lapped it to the seat the best I could with some valve grind compound. The problem was that the rebuild kit isn't for this exact carb, so the needle and seat were wrong for the float. I then figured it was pretty good and put it back on. Nope, acceleration pump still doesn't work (not the end of the world), still can't get it to idle, and under pump pressure the needle and seat still leak too much so the height is wrong.

I guess I can throw a shim in the seat (how you do coarse adjustments) and make the height way lower to see if that works. Or try to get a new needle and seat for it. I don't know, the whole thing is just a mess of corrosion and pitting. There is a similar carb available as a "new" knockoff, I don't know if that's just a bad idea.

The other issue is I have no way to set the timing as per the manual because I can't go below about 1000rpm or it just dies. I think I might be able to extrapolate out what safe timing is, I'll have to do some reading. It seems like the position for the distributor that is most likely to be right is between the options for what tooth you engage and how far you can adjust it.

Anyway, it actually runs pretty good at about 1500-2000rpm. If I had a functional temperature gauge I'd probably just use it and accept it won't idle.

[Scott Cee AKA 2drx4]

This might be the $120 solution to all of life's problems. Gotta do some measuring to see if it will fit.

[arse_sidewards]

I would do an adapter to a more common domestic 1bbl Jeep carb because there's a million times more tuning documentation out there to help with your issues and secondarily it will probably save you $60 (syrup bucks, so like 3.50 freedom bucks).

[Scott Cee AKA 2drx4]

I would do an adapter to a more common domestic 1bbl Jeep carb because there's a million times more tuning documentation out there to help with your issues and secondarily it will probably save you $60 (syrup bucks, so like 3.50 freedom bucks).

I'm not sure what 1bbl carb was used on Jeeps. All of the newer stuff used some 2bbl Weber crap I think, and guys swap them out for the Ford 2100/2150 normally. There's a Ford 1100 that's 1bbl that can be had fairly cheap and was used on a bunch of their I6 cars. The Ford 2100 looks like it might fit though, and they're about the same price as the Toyota/Suzuki one I posted, so it might well fit. Lots of the other 1bblk stuff is either up draft or side draft, which isn't going to play well. There's some 1bbl crap for Harleys that seems common too, looks like its down draft and you know there would be lots of (potentially bad) info and jets/etc available, but the last thing I want is for this thing to run as poorly as a Harley.

I'm going to try again to get the float height more where it should be and measure the base plate on this thing while I have it off. I guess if I was thinking I could have grabbed some lapping compound while I was in town to try to get that seat and needle better.

[arse_sidewards]

Yeah, everyone with a brain runs an autolite/ford 2xxx in a 2bbl application.

I was figuring there's probably some carter 1bbl that was used in a range of applications and that the Chinese are knocking off in the same manor that they're knocking off Zenith updrafts and then selling them for every 20-50hp updraft application with no fucks given if it's "right" and that if you search "Jeep CJ carb" you'd be able to find whatever carb the Chinese have decided is going to be the one that gets supported going forward.

[Scott Cee AKA 2drx4]

I spent a bunch more time on the carb and managed to get the idle circuit to work. Turns out it was my fault, there's an adjustable orifice in it that wasn't mentioned in the manual, but was obvious when I looked at it again. That said, the carb is still a total POS. I can get it to idle at about 750rpm (spec is 650) and it will die if you pull the throttle back fast. With it all warmed up the machine is usable, but super bitchy to restart if you shut it off while hot.

The needle definitely leaks a bit still, so I tried putting a shut off valve in the fuel line so it at least wouldn't gravity fill the engine up. The valve leaked everywhere, so I took it back out and put vice grips on the line for now. Annoying.

The other obvious thing that I realized is the vacuum advance on the distributor does not work. That isn't going to help with general running. I will have to look for some more parts for that.

[Scott Cee AKA 2drx4]

So I figured I might as well take the distributor apart because a "new" one is $250-300. There is some 4G63/4G64 ones for only $120, but there isn't really any way to say they're the same. I don't want to chew up my cam either, because they're unobtanium.

Basically I gave it all a cleaning, dressed out some grooves, flushed out the vacuum actuator, and put it back together with new grease and dry graphite.

End result is it still sucks. The vacuum advance does move, but not much. I dialed the base timing up to 15 degrees because fuck it at this point. It runs way better like that. I suspect that given the low compression ratio and if I only put purple gas in it that this will never cause any issues. Really the main issue now is that it does not have a functioning accelerator pump and if you jam the pedals hard the engine does fuel starve, and there is nothing I can do to fix that on this carb.

The other possibility is that the vacuum advance is hooked to the wrong port. This seems unlikely, but there is a plug in the manifold where there likely had been a port of some sort.

Speaking of gas, it did occur to me that the machine is full of fuel from God knows how long ago. We threw some fresher fuel in it on top of what was in there when I went to buy it, but otherwise it might be a bunch of 2+ year old gas. So maybe I'll dump it out and put fresh stuff in, since it might matter for this sort of thing.

[arse_sidewards]

Unless it has water in it it should run.

Any time I've had fuel "go bad" there were other problems (rust, corrosion, varnish) involved that precluded just dumping new fuel in.

[Scott Cee AKA 2drx4]

Unless it has water in it it should run.

Any time I've had fuel "go bad" there were other problems (rust, corrosion, varnish) involved that precluded just dumping new fuel in.

I'm tempted to dump it and use it to start my brush pile on fire, just so I can say I did put fresh gas in it, but yeah, there is no water or goop in it that I can tell. The machine was inside of the PO's shop the whole time, then inside mine, and I've had the lines off enough times to see nothing but clean fuel come out of it.

I'm going to look at the vacuum diagram for the Colt to see where the vacuum for the advance was taken on the car.

[Scott Cee AKA 2drx4]

I did buy a new carbertooter, but I haven't put it on yet, and may not:

It was the one I posted a screen shot of before, and I found the same one is listed as fitting "Bobcat 642B 742B" in different listings. The ones listed as fitting the Bobcat are $500~ though. Neither would be a bolt on. For the time being I'm going to try to run with the one I have and see if it's worth it.

My little bracket and fuel shut off:

It's the exact same valve (same brand even) as the one that leaked, but this one came from Amazon for half the price and so far hasn't leaked.

And I switched the vacuum source for the distributor to the manifold:

There was a plug in that port, but it was the tight JIS style of NPT, so I had to open it up with a tap. The plug was the same style as all the OEM Mitsubishi bolts. Based on that I'd say there was no evidence that this port had ever been used on this machine, meaning I am definitely changing how this works. The vacuum source they had been using was ported, or maybe semi-ported, it took vacuum off right at/below the throttle blade. Honestly I think this makes way more sense, the thing runs way better, and I was able to reduce the base timing to about 10* (again, they call for only 5*, but screw 'em), and now I've got lots of advance at idle and mid power. Yeah, the vacuum advance does work, and it actually does what the manual says it should with it hooked up this way.

I also drained most of the gas out and refilled it with some fresh purple stuff. I doubt it made any difference but whatever, I needed some for the burn pile anyway.

Honestly it now runs well enough I'm willing to just try it for a while. It still has a few issues that need to be fixed and some that should be. The throttle at the machine side needs something adjusted or is missing a spring, or the wrong spring is on the governor, as if you set it to full RPM it just slowly wiggles the throttle lever back until you get 2000-2200~RPM. The parking brake does not cut the drive motors off, I suspect it just needs an adjustment. The temperature gauge doesn't work, the sender is dead and NLA, there is a new style sender but I might have to buy a gauge too as likely it has never been replaced. The heater doesn't work and I didn't run the hoses and don't know what I want to do with it anyway. The lights don't work and probably should be replaced and rewired. I should probably put a blinky light/rotating beacon/orange triangle of not caring on it because I do pull on and off the road when plowing my driveway. The seat is all torn up. The "glass" (it's a big piece of lexan or plexi) in the door is falling out and scratched to shit, I should at least glue it back in and maybe add some corner bolts, and possibly give it a buffing. The wiper for it is also missing and who knows if the motor works, I guess I could try it, but a wiper on a plastic window tends to cause more trouble than it solves. I want to put some mesh over the vents in the rear door so nothing gets dropped in there and goes into the belts, probably being paranoid but if I can find some fine expanded steel and bolt it on it seems worth it. Potentially none of this will ever get fixed because I'll decide it's good enough since I won't use it that much.

Anyway, finally went and retrieved its bucket and used it to move a bunch of snow around and stuff:

[Scott Cee AKA 2drx4]

A few other P/Ns for the googlers (or me later):

Radiator cap: Stant 10228 (This is a direct cross with the Bobcat P/N, they want several hundred dollars for it though)
Thermostat: MotoRad 5240180 or 5240-180 or 45868
Distributor rotor: Standard Motor Products JR80
Distributor cap: Intermotor JH67
Plug wires: Denso 671-4007 or 6714007
Coil: Standard Motor Products UC12 (this coil works way better than the one that was in it)
Oil filter: Hastings/Baldwin LF144 (meets/exceeds the specs of an OEM filter)

Maybe I should put together a full parts list at some point.

[Scott Cee AKA 2drx4]

Okay, more comprehensive list for the Googlers:

Parts list for Bobcat 4G32 rebuild:
Main bearings: ITM Engine Components P/N 5M1147 (5M1147-020 for 20 under) Application 1981 DODGE COLT 1.6L 98cid L4
Rod bearings: Mahle/Clevite P/N CB1120A4 (CB-1120A-.50MM(4) for 20 under) Application 1981 DODGE COLT 1.6L 98cid L4
Pistons: Safety Auto Parts P/N SP-902 (SP-902-3 for 30 over or maybe SP902.030) Application 1985 MITSUBISHI MIRAGE 1.6L 98cid L4 Turbocharged (Note, these may no longer exist, not sourced through Rockauto)
Rings: Safety Auto Parts P/N 2C675 (2C675030 for 30 over) (Note, these cross to a Hastings set that fits the N/A Colt engines, but they are what the piston manufacturer specs, they appear to just be a thicker ring than what was used originally with the Mirage)
Valve guides: P/N 1407576 and 1407577 (Note, not sure which is intake and exhaust or manufacturer)
Gasket kit: FEL-PRO P/N HS8974PT Application 1982 DODGE COLT 1.6L 98cid L4 (Note, is the top end only, but has a nice MLS headgasket)
Gasket kit: ITM Engine Components P/N 0900302 or 0900302:8 Application 1982 DODGE COLT 1.6L 98cid L4 (Note, complete set but the intake gasket is wrong, the FEL-PRO kit has this gasket or see below)
Intake manifold gasket: APEX P/N AMS2190 Application 1981 DODGE COLT 1.6L 98cid L4 (Note, didn't use this one but it looked correct)
Intake manifold gasket: ITM Engine Components P/N 0950345 or 09-50345 Application 1981 DODGE COLT 1.6L 98cid L4 (Note, this P/N is the same as a FEL-PRO gasket, but I believe it is NLA)
Timing belt: ITM Engine Components P/N 4105 Application 1989 DODGE COLT DL 1.8L 107cid L4 (Note, may also be a Mitsuboshi CD93, not confirmed)
Timing belt tensioner: BECK/ARNLEY P/N 0241090 or 0241090:8 Application 1989 DODGE COLT GT 1.6L 98cid L4 Turbocharged (Note, had P/Ns 552-294 and MD109958 written on box, SKF P/N TBT75101 may also be right)

Carb kit: WALKER PRODUCTS P/N 15581B Application 1977 DODGE COLT 1.6L 98cid L4 (Note, does not have correct needle or seat)

Plug wires: DENSO P/N 6714007 or 671-4007 Application 1982 DODGE COLT 1.6L 98cid L4
Distributor cap: STANDARD MOTOR PRODUCTS P/N JH67 or JH-67 Application 1977 DODGE COLT 1.6L 98cid L4
Distributor rotor: STANDARD MOTOR PRODUCTS P/N JR80 or JR-80 Application 1977 DODGE COLT 1.6L 98cid L4
Spark plug: Autolite P/N 66 (Note, these are what Bobcat specs but can be replaced for any similar plug or better. They are probably not worth the premium for a very old design of plug if you've upgraded to electronic ignition)
Electronic ignition upgrade: Pertronix P/N 1941
Coil: STANDARD MOTOR PRODUCTS P/N UC12

Thermostat: MOTORAD P/N 5240180 or 5240-180 Application 1977 DODGE COLT 1.6L 98cid L4
Radiator cap: STANT P/N 10228 (Note, no application specified, is a direct cross to the Bobcat P/N)
Radiator hose: Bobcat P/N 6571683
Radiator hose: Bobcat P/N 6571682
Temperature sender: Bobcat P/N 6658818 (Note, available aftermarket but pricing is similar to OEM Bobcat, for use with new style gauge P/N 6669663 only, sender P/N 6599492 for old gauge is NLA)

Belt (waterpump): Continental P/N 11AV1030 or 15411
Belt (governor): Continental P/N 11AV800 or 15321
Air filter: Bobcat P/N 6646494 or Luber-Finer LAF1275 or NAPA FIL 2276 or 2276FR
Oil filter: Bobcat P/N 6696286 or WIX 51324 or Donaldson P550935 or Hastings/Baldwin LF144 or B173-S or NAPA FIL 1381 (Note, NAPA is a direct OEM cross, the others are similar and may offer slightly different filter efficiency)

Muffler: Bobcat P/N 6514737 (Note, buy generic aftermarket, they're all over the internet)
Exhaust flex pipe: (Note, correct part is NLA, used a 6569624 generic aftermarket and cut it down to fit)

Starter: Wilson P/N 91014247 or 91-01-4247 (Note, purchased but still running starter it came with, plan to swap it out as Bendix drive is damaged)

Parts I didn't get:
Oil pump rotor: Bobcat P/N 6632733 (Note, NLA from Bobcat, might be some dead stock out there. Aftermarket part 6632733-AM was shown as existing, but no stock. Ultimately I determined my rotor was fine, gerotor pumps don't wear quickly)
Oil pump housing: Bobcat P/N 6660302 (Note, NLA from Bobcat, there is used units available but not much point in buying one unless you were to use it to attempt relining the pump housing. Dodge Colt part is different)
Water pump: Bobcat P/N 6632822 (Note, available but very expensive, decided to reuse the one I had. There is now some listings of knockoff/aftermarket ones. Purchased a Dodge Colt waterpump and it could be adapted but not easily)
Distributor: Cardone P/N 31649 or 31-649 1981 DODGE COLT 1.6L 98cid L4 (Note, this is an electronic distributor but should just be plug and play, I cleaned/repaired my existing distributor instead. Bobcat part is NLA)
Alternator: Wilson P/N 90317000 or 90-31-7000 (Note, alternator I had is fine, but would like to have a spare. This alternator is not cheap, I suspect a GM 1-wire "Delco 10SI" type could easily be adapted)