Going to pick up an old 632

[spitzair]

I don't know what 30 and 40 series means, but point taken. Maybe I'll just use the tank I have and mount it to the right of the engine. There's lots of room there to do that.

By 30 series I mean 630, 631, 632, 730, 731 and 732 machines, 40 series machines are 641, 642, 643, 741, 742, 743 etc. machines... You can probably use the parts diagram for a 642 to show you exactly how and where it's mounted if need be.

 

[brdgbldr]

That new tank you have fit into what Bobcat called a “shield”. It is just a “J“ shaped bracket that the tank friction fits into. The part number is 6709415 if you want to take a look at it in the parts catalog to get an idea of what it looks like. Bobcat still has them in stock but they want $193.12 for what is easily made with some sheet metal.

 

[Ster1]

That new tank you have fit into what Bobcat called a “shield”. It is just a “J“ shaped bracket that the tank friction fits into. The part number is 6709415 if you want to take a look at it in the parts catalog to get an idea of what it looks like. Bobcat still has them in stock but they want $193.12 for what is easily made with some sheet metal.

Come to think of it, I’ve seen those before. Although I believe it was on the left side of the engine on the machine I was working on at the time. Anyway, yeah I’m going to make one up and mount it to the right of the engine. Plenty of room there. Thanks!

 

[Ster1]

By 30 series I mean 630, 631, 632, 730, 731 and 732 machines, 40 series machines are 641, 642, 643, 741, 742, 743 etc. machines... You can probably use the parts diagram for a 642 to show you exactly how and where it's mounted if need be.

I called a dealer yesterday and he said the part was superseded to the part that I have. So those square tanks are indeed rare as hen teeth. That’s probably a good thing. That tank is ready to shatter into a million pieces. I bet if I dropped it on the floor it would go “poof”.

 

[Ster1]

I finally did a proper lapping job on the valves, and got much better compression. Originally (before new rings etc) it was 120-90-40-105. Now I got 100-95-90-90. I bet it will get better once the rings wear in. I'm in Denver, so 90 on a static compression for an old gasser is not great, but workable. At least they're now alot closer to each other. I'm still having a misfire at #1, it's colder then the others. Don't know why yet, that's my best cylinder I think I'm getting closer to a good engine though. I think I was having issues with my fuel pump too, the old mechanical one. I have enough gas in the tank to get a gravity feed working, and I just bypassed the mechanical pump, and the engine started up much faster today. I think I'm going to remove that mechanical pump, and block off the hole, and install a clicky - clack pump.

 

[RandyL]

When I went through my engine a year or two ago I wanted a new fuel pump just to have it new. Kind of hard to find as most car pumps have the fuel line slightly different and the line hits the factory manual choke linkage. I thought about going to a cable choke, but kept searching and found the fuel pump I wanted so I am still all original style.
Low compression is what made me pull my engine and go through it. Ring end gap is normally in the .012 range. I had nearly 1/4 inch! The head specs showed warp allowed .000 - .005 as good. Mine measured .005 so I had it milled back to .000. Luckily, my block was perfect. Sounds like you are getting yours all worked out. Its nice to have it start right up and run smooth.
As it is someone will get a machine with a good engine as I will be selling it. I no longer have a use for it as all my land work is now finished. Hard to justify having it just to dress the driveway once a year.

 

[Wayne440]

...someone will get a machine with a good engine as I will be selling it. I no longer have a use for it as all my land work is now finished. Hard to justify having it just to dress the driveway once a year.

If it is paid for, you might as well keep it. About 3 days after you sell it, some job will come up where you will think "why the #$%^ did I sell that machine?"

 

[Ster1]

I'm going to second what Wayne said. I bought an Allis Chalmers D15 with a loader to help me with my backyard a year or so ago. Once the job was done, I sold the tractor. I live in the suburbs, so that thing was way too big to keep, but since I had a loader for awhile, I found lots of uses for it. It's like a pickup truck, you don't think you want one until you get one, and you find out you can't live without it. Just today though, I picked up a Mitsubishi mini tractor with a loader on it. 2 cylinder diesel, but the head is cracked. I'm going to either fix or replace the head, and that little guy is going home with me

 

[Fabricator]

Another vote for keeping it. I bought my Bobcat 630 over twenty years ago intending to use it to help out with building a workshop and doing some landscaping chores and then sell it again once I was finished. Needless to say, it's still here and does everything from clear out the neighborhood when it snows, moving things around in the workshop, more landscaping projects, and unloading supplies for the workshop.

 

[spitzair]

I too am in the keep it camp! I grew up on a small farm in the middle of nowhere and we had a 732 around since I was 9 years old. We used it every day for something. I now live in town on a regular size lot and bought another 732 to fix up and use to build my garage and the odd other project. It is just way too handy to have around and although here it may go for a few weeks without being used when you need it you need it, from something like loading or unloading a piece of whatever from the back of the truck to pushing snow to really anything you can think of. If I had to rent/borrow a machine or even wait for the neighbour to have time to do a little something with his it would add hours or even days to some projects if a machine isn’t available… plus it’s a great little cash generator when someone needs a machine for a job that others don’t want to deal with because it’s only an hour or so of work…

 

[Fabricator]

If I had to rent/borrow a machine or even wait for the neighbour to have time to do a little something with his it would add hours or even days to some projects if a machine isn’t available…

This is the main thing for me. Without the Bobcat I'd probably pass on doing a lot of things. Now, it's just like "I'll just grab the Bobcat and get it done."

 

[Wayne440]

I decided a long time ago not to sell a machine until I have a replacement for it. This revelation came to me after I bought a small ride-on trencher and used it for several jobs around the house-then sold it. About 3 months later, I had a job for a trencher- bought one costing 3 times as much as what I got for the first one. This one isn't going anywhere until an equally capable machine replaces it-even though it gets maybe 5 hours a year of use.

 

[bobcatzack]

60 views and no replies. Crickets. Oh well, I’ll just talk to myself then. I brought it home, and as far as the starter is concerned, the motor was locked. I mixed up some 50/50 acetone and ATF, and dumped some into each cylinder, and left it for a few days. I tried again today, hooked it up to my jump pack, and yep stuck. The starter couldn’t budge it, but a big a$$ pipe wrench on the pulley sure could! Had to work it back n forth a couple times, but I got her spinning. Tried the starter again, and it cranked for awhile. Long enough for oil pressure to build, and to see the hydraulics were at least trying to work. Next up is a new battery and a compression check.

Hi Ster1, wishing you the best with this new "older" bobcat 632! You can't beat the joy of getting these going and see them come back to life! I myself is a complete novice at this. I wanted to grade about an acre in the back area of my home (Illinois) and ended up buying a Bobcat 632 too. It used to start and run, but the water pump leaked, and the radiator got really hot and boiling. In any case, I tried to clean up the engine and ended up using a spray engine cleaner, then hosed it down with water. Well, after that, the bobcat took a while to start (I jumped it with my car battery) - when it started it ran for a while, ten sputtered and came to halt. Since then, I not been able to get it started - it cranks really well. I studied what could have gone wrong? Some of the wires got soaked and broke perhaps? I changed all the 4 spark plugs with new wires leading to the distributor. I bought a spark plug tester and I see sparks when I crank the engine. I bought a compression tester and compression seem to be ok too. Then i wanted to focus on the fuel intake - the Bobcat parts website has a nice page (see below link) if you search on 2nd tab for Model 632, it mentions a Solenoid Shutoff Valve. I was wondering if I should focus on this solenoid? Should I try to remove the carburetor and try to clean it? Any advise will be highly appreciated!

Bobcat Genuine Parts Catalog – Official Bobcat Company site

 

[spitzair]

Zack, Are you still running points and condenser in your distributor? If so, there’s a real good chance your condenser went south and/or or your points are out of adjustment. They are very fussy and it simply will not run if you don’t get them set just right even if you do see a spark. On the 732 (same engine as your 632) I purchased 6 years ago that the biggest contributor to it not running when I bought it. I switched it over to solid state ignition and it made a huge difference! I recently converted my dad’s 732 as well and he says it’s way better now as well.
Definitely worth looking at and cleaning your carb too, and if it does have the electric solenoid on the carb it could cause an issue. You don’t really need it, it’s mainly there to prevent dieseling on shutdown, but if it doesn’t work you won’t get fuel and thus no start. I think you can just remove it and plug the hole but not 100% on that… all I know is one of my 732s has one and one doesn’t…
Hope this helps a bit.

 

[Ster1]

It’s either the fuel or the fire. Put your timing light on each lead while you crank it. That will tell you if you’re getting spark. If not, maybe you got your distributor wet on the inside and tried to start it, the rotor and contacts inside the cap may be caked up with crap. Take a little file or piece of sandpaper and clean em up till they’re shiny. Spray a little ether while cranking. Does it run on ether? If so, this looks like a fuel problem. That fuel solenoid is definitely a culprit. Just pull it out, cap the wires and plug the hole. It’s flaky. I always start troubleshooting with ether. It tells ya a lot right off the bat.

 

[RandyL]

Hi Ster1, wishing you the best with this new "older" bobcat 632! You can't beat the joy of getting these going and see them come back to life! I myself is a complete novice at this. I wanted to grade about an acre in the back area of my home (Illinois) and ended up buying a Bobcat 632 too. It used to start and run, but the water pump leaked, and the radiator got really hot and boiling. In any case, I tried to clean up the engine and ended up using a spray engine cleaner, then hosed it down with water. Well, after that, the bobcat took a while to start (I jumped it with my car battery) - when it started it ran for a while, ten sputtered and came to halt. Since then, I not been able to get it started - it cranks really well. I studied what could have gone wrong? Some of the wires got soaked and broke perhaps? I changed all the 4 spark plugs with new wires leading to the distributor. I bought a spark plug tester and I see sparks when I crank the engine. I bought a compression tester and compression seem to be ok too. Then i wanted to focus on the fuel intake - the Bobcat parts website has a nice page (see below link) if you search on 2nd tab for Model 632, it mentions a Solenoid Shutoff Valve. I was wondering if I should focus on this solenoid? Should I try to remove the carburetor and try to clean it? Any advise will be highly appreciated!

Bobcat Genuine Parts Catalog – Official Bobcat Company site

It sounds like there is moisture in the dist. In the day when point type dist were in everything, what you say was common place. An engine would start wet after a wash job but after it ran a bit it would die and not restart. Droplets of water that got into the dist would vaporize to steam and coat everything, short it all out...and die. Take your dist cap off for a day and let it all air out. It can hold moisture for days and days if not dried and aired out. As a side note..my 632 does not have a fuel solenoid. Some do and some don't it seems.

 

[GreenwoodCreations]

Bobcat was known for making service changes and NOT recording when it was done by serial number. Books just show a line of x’s indicating a change an the new part number of added part

 

[bobcatzack]

Zack, Are you still running points and condenser in your distributor? If so, there’s a real good chance your condenser went south and/or or your points are out of adjustment. They are very fussy and it simply will not run if you don’t get them set just right even if you do see a spark. On the 732 (same engine as your 632) I purchased 6 years ago that the biggest contributor to it not running when I bought it. I switched it over to solid state ignition and it made a huge difference! I recently converted my dad’s 732 as well and he says it’s way better now as well.
Definitely worth looking at and cleaning your carb too, and if it does have the electric solenoid on the carb it could cause an issue. You don’t really need it, it’s mainly there to prevent dieseling on shutdown, but if it doesn’t work you won’t get fuel and thus no start. I think you can just remove it and plug the hole but not 100% on that… all I know is one of my 732s has one and one doesn’t…
Hope this helps a bit.

Many thanks for this advise, highly appreciated! I am more than willing to switch to a solid state ignition - can you please suggest what electronic ignition module I would need to buy? Will that be available at an auto parts store? After I read your post, I also looked up on YouTube and perhaps this following video might provide some guidance when I get around to switching over to solid state ignition:



Hope I am on the right track with this video? Any additional advise would be invaluable to me (as I am a complete novice at this!).

 

[bobcatzack]

It sounds like there is moisture in the dist. In the day when point type dist were in everything, what you say was common place. An engine would start wet after a wash job but after it ran a bit it would die and not restart. Droplets of water that got into the dist would vaporize to steam and coat everything, short it all out...and die. Take your dist cap off for a day and let it all air out. It can hold moisture for days and days if not dried and aired out. As a side note..my 632 does not have a fuel solenoid. Some do and some don't it seems.

Thanks for the reply Randy! In another post, there was suggestion to potentially switch to solid state ignition - which I will attempt to do. About the solenoid, I keep peaking behind the carburetor and I do see something like a solenoid, but it has a rusty wire hanging that seem to go nowhere!

 

[Ster1]

We kinda wandered off in the woods for a little, but here’s another little update on the little bobcat. The valve job helped quite a bit, but I made a few more changes. I installed a clicky-clack fuel pump, and ran it to the ignition so I can fill the float bowl before cranking the engine. That made a big difference in how long it took to start. I also installed a Pertronix ignition to replace the points. I also found that the flex hose nipple on my intake manifold was for a 3/16 hose, but the nipple on the advance unit on the dizzy was for 1/8, or in any case, smaller, and I never noticed. What that translated to was a vacuum leak, and the vacuum unit actuating erratically, which contributed to my engine running rough. So, hose replaced with a gooder one. Now the engine starts much more easily, and runs fairly smooth. It’s still surging a bit, which may be the governor. I have a fair bit of blowby, so my rings could be better, but once it’s hot, the blowby goes down a little. I’m hoping once those rings seat in, it’ll be better still. I also finally replaced the water pump, so it’s now got proper coolant and I ran it hot yesterday. The engine ran better the more it ran, but I ran out of time and had to pause.

Today I’ll run it a bit longer, and try to determine if my surging is because of the governor or just the engine still stumbling a little. Since I have as much blow by as I do, I am assuming it’s the engine just not running quite right.