Interesting that it doesn't have the window, is it an original carb or did it come from a car? Does the needle look like mine or like the one from the kit that didn't fit my carb?
In my later model 742B (with the two piece axles) the carb did not have the window either. Also, I had a brand new carb bought in 2015 that did not have the window.
After a lot of picture research for various Dodge colt water pumps, I bought a water pump for a 1978 dodge Colt--an Aisin WPM 006. It was an exact replacement for the one I took off my 742B with the 4G32 engine, and which appeared to be the OEM water pump. For research, I also ordered a 2nd one, also for a 1978 Dodge Colt made by GMB Lazorlite L 31-1049 ($18, the cheapest I could find). The casting appeared to be identical to my original, the impeller was different, but I assume it would work. I got both from Ebay. Rock Auto might have been slightly cheaper for Aisin, but their shipping is pretty high. I recommend the Aisin. There seem to be many available from $40-$70, but I suspect everyone is clearing out their old stock so they may not last long. I also later noted that the overflow tank for the radiator is below the radiator, meaning that if the water pump shaft seal begins to fail, the radiator will preferentially suck in air past the shaft seal rather than the heavier antifreeze mix in the overflow tank, and on the next warm-up cycle spit out a similar amount of water from the engine through the water pump shaft seal. Since no one is going to unbolt the outside cover frequently to expose the radiator cap to check the level, making sure the water pump is in good shape (i.e. not horribly old with failing seals) is really important. Your beautiful like-new engine deserves a new pump.
One thought on swapping carbs--Bobcat went to a lot of trouble to de-tune this engine--definitely low compression pistons (~7.5:1 vs 9:1), blocked carb secondary when a straight off the shelf 2 bbl version would probably have been cheaper, and the less than optimal vacuum advance. And the cam--who knows. The ultimate result was an engine rated at ~ 100 hp (albeit at a higher rpm) now putting out 36. I suspect somewhere in the hyd system is a pump shaft that is designed for a max of ~ 40 hp, and giving it more will only be likely to break it. A carb designed to actually serve fuel and air to a ~1600 cc automobile engine @ ~5000 rpm would probably increase the Hp of this engine, possibly to catastrophic levels for the parts it drives. Be cautious.
I'm pretty sure mine is OEM. Also 2 piece axles. The end that connects to the float is like your original one. I didn't have any shims in mine. It seemed to be running rich, so I bent the float tab a little, eyeballing the float to sit more or less level when held upside down and in place, although it was pretty close to begin with. But I would like to be able to do better and know I had it right. I also didn't get what I would call proper adjustment out of the idle mixture needle--it didn't seem to make much difference, which along with smelling rich was what got me into the carb. I didn't find anything there to fix other than a minor change in float level. I also couldn't find any info on the off-idle adjusting screw that is part of the idle circuit.
To get it out doesn't take too long, I think it took me a week of evenings working on it and cleaning stuff as I went. You can have it out in about 4 hours if you know what you're doing. You can pull the head off with it in the machine, there is plenty of space. Also, you can take the valve cover off super easily (it's two hoses, 2 bolts, and you have to pop the cap off the distributor to get the wires out of the way), and that might tell you right away if one of the valves has dropped out. It's not an interference engine, so it would only be if a valve has lost its keeper and dropped completely. You also should be able to see that by looking in the #1 spark plug hole.
I wish I knew that before. Everyone just said mid-80s Colt, and all of the ones I looked at were like the one I purchased that is wrong. The Asin part is on eBay, but huge shipping for me, there does not appear to be stock anywhere else. I was able to get a Dayco P/N DP1182 for $21 CAD ($15 USD~) off Rockauto, and I threw an extra timing belt in the order. They had a couple other ones that looked right too.
Ah, that happens. They simplify the part to save costs, and in so doing make it very hard to work with.
I thought about it a lot, but didn't really hash out my thoughts here. Their detuning of the vacuum advance likely is contributing to engine failure. They dropped the compression enough by using the turbo pistons that they reasonably could have run a lot more timing without any risk of detonation, and the lack of timing along with low compression was definitely leading to incomplete combustion. Incomplete combustion isn't great for valves, rings, the cylinder bores, etc. Changing the vacuum advance how I did will just lead to better combustion and running at part throttle and idle, effectively meaning that it makes more power with less throttle, but will limit full throttle power to about the same as before (it's a bit of a wash, throwing more base timing at it will definitely increase power a bit for sure though, and I did that). The correct factory solution to decrease power would have been a restrictor plate (Nascar does this) or a throttle stop, along with the complete lack of the secondary circuit in the carb.
Yes, a good suggestion but scary in that the zinc is thin and brittle. Going to have to give that some thought anyway.
The water pump I replaced had the impeller facing the opposite way, as did the replacement. I didn't look at the engine for how the coolant came in and went out since both were identical. A 2nd water pump of a different brand that was otherwise identical looked like these. So no idea if it matters.
The impellers on these ones match what is in my machine. I'm guessing it doesn't matter much either way.
I would try the parts stores for something generic and metric that would fit a 1978 Dodge Colt. Failing that, I would consider buying a pipe tap and a short hopefully brass nipple and re-tap the hole to an American thread and just use a pipe nipple. Or maybe McMaster Carr has metric pipe nipples.
For the rings I used, one was tapered, so it was the upper ring and the taper faces up, the other was straight and did not have any markings, so it's the lower ring and can go either way. Hold them against a piece of white paper or similar to look at the edges to make sure. I did not use the rings you purchased, as I purchased ones for a turbocharged car, so they may be different. All of the forklift parts I purchased turned out to be incorrect.
