K91 Tin's For RJ-58 Question

[71_Bronco 1,072]

I am putting together a K90 / K91 for my RJ-58, and am trying to figure out which sheet metal pieces are supposed to be on the motor.

I have the main one on the side (that covers the flywheel, and has the ID tag on it), I have the top piece (that covers the head & all head bolts, with a hole in it for the spark plug), and I also have the one that wraps around the side of the top section of the motor.

I tried looking in the picture gallery's, and it looks like I should use all 3, but I just want to double check before I go through all the work of straightening, stripping & painting all the pieces.

Thanks!

[MikesRJ 552]

The pictures below should give you everything you need. Pictured is a "correct" configured K-90 engine. You should be using all three, with the addition of the rope pull-start underneath the Schnake recoil assembly.

[71_Bronco 1,072]

Thanks. I do have all three like you show, so I will be sure to use them all.

My recoil starter and air cleaner are going to be incorrect then. My recoil starter looks like the one below, I found a guy who had a NOS one found in an old warehouse, came in the old Kohler box.

As for the air cleaner, it will look similar to the one below. Again, was a NOS item found in a warehouse, but not the same one as the recoil starter was in.

My carb looks almost identical to yours, mine is a "Carter model", although not as clean as yours lol

Thanks again

[MikesRJ 552]

Before I acquired the correct Schnake recoil for my RJ, I used the same one. The air cleaner you show was installed on the K-91 engines standard from the factory. The down-draft oil bath air filter shown on mine was installed on the earlier K-90's.

[71_Bronco 1,072]

Before I acquired the correct Schnake recoil for my RJ, I used the same one. The air cleaner you show was installed on the K-91 engines standard from the factory. The down-draft oil bath air filter shown on mine was installed on the earlier K-90's.

Thanks again for the help. Now that I know what to look for as far as the recoil start goes, I will be on the look-out for one, using the one I have in the mean-time.

One last question, what should I look for as far as the oil-bath air filter? Is there any brand? Or is it a Kohler, just a different model? I also would need that 90 degree piece (that transitions the horizontal carb inlet into the vertical inlet for the filter).

Thanks! And thats a really nice RJ you got there :handgestures-thumbupleft:

[MikesRJ 552]

The "correct" answer depends on which engine specification, and therefore which year, you are trying to build. If you are making a K-90, then the Oil-Bath model is correct. If making a K-91, then the Kohler pancake style is correct. I am not 100% sure but (perhaps 98%) I believe the United Specialties oil-bath air filter's only came on the K-90's, and the newer (than the k-90) K-91 model engines came with the Kohler pancake model air filter.

The oil-bath air filter was manufactured by United Specialties Company of Chicago, IL. The filter housings are no longer available new, but do come up on eBay from time to time, and there are two types you should be mindful of. One was an up-draft (this is the one you are looking for) and the other a down-draft (not preferred). The difference is the direction of airflow. What you want is the one with the carburetor connection on top.

You can convert a down-draft to an up-draft, though I had the member here, Wallfish, convert mine and he would be better than me to tell you how to do that. Also shown in the image below are the correct decals which would have been affixed on an original K-90 installation.

Thank you for the compliments. There is an entire write-up of that restoration if you care to take a look. It may give you some more needed information concerning your restoration: http://www.mywheelhorse.com/modules.php?name=docs2&do=show_doc&id=2

[71_Bronco 1,072]

The K90 I am using (well, the base motor) was off a Bolens Ride-A-Matic from what I was told. The numbers I got off the tag was K90, a serial number of 236-365, and a spec number of what looked like 7C1A.

Those numbers were pulled in a hurry, and am not 100% sure on them. I pulled the tag off last night when I was looking at my starter & my tins, and I can get a definitive answer of what it says tonight. The motor had no carb or air cleaner (carb came off the K91 parts motor), and the starter was one of the ones where you wind the rope around by hand and pull, and if it didnt start, re-wind it and re-pull. That's why I went with the recoil starter, as it was more correct from what I saw, and allot easier. That and I didnt have the pull rope, so I would have had to buy that anyways.

[MikesRJ 552]

The correct spec K-90 would be K-90-27107D, the correct spec K-91 would be either K91-31307A, K91-31388A. K91-41437A, or K91T-31388A.

That said, the spec numbers indicate the configuration of the engine. Here's a list of all the K-90/91 manuals I have:

K-90-27107D OM - IPL

K90 / K91 Replacement Engine - Installation Instructions Manual

K90 / K91 Service Engine Descriptions

K91-31307A OM - OM-2 - SM - SM-2 - IPL

also includes;

K91-31388A

K91-41437A

K91T-31388A OM - OM-2 - SM - SM-2 - IPL - OPS

[71_Bronco 1,072]

Here is basically what I have for the most part. I know a few things are missing (like the governor arm and spark plug wire), but I do have all the stuff in a small parts box.

I am looking at my motor tag now (you can see its not on the flywheel cover), and the tag says this:

-Model No. - K90

-Serial No. - 236 365

-Specification No. - 7C1A

2739A (not sure what this is, no label above it)

-Plug - .025

-Points - .020

-Valve Clearance - .008

-Oil, Pints - 1.5

EDIT: Sorry the motor is so dirty, the reason why its "2-tone" is cause some parts came from a second motor (orange obviously lol). It will look allot better when its repainted. I am still waiting on a gasket overhaul kit and a few other small parts (seals & bearings), then it will get torn down, cleaned up, repainted & rebuilt.

[MikesRJ 552]

2739A is most probably the spec number, not sure what the 7C1A is though. It doesn't match any of the information I have.

[71_Bronco 1,072]

2739A is most probably the spec number, not sure what the 7C1A is though. It doesn't match any of the information I have.

I will take a pic of the tag tonight so you can see what I am talking about.

One last question. The 90 degree exhaust "manifold" that is shown on my motor, is that correct to the RJ's? It was on the K91 parts motor, and thought it would be an easy way to do the 90 degree turn. Also, I can tap the end of it for straight pipe. I figured it would be easier then tapping the block, and making sure a 90 degree elbow is pointing in the correct direction. I think it will look good once I get it all cleaned up.

[MikesRJ 552]

Pictures are always worth a thousand words ...

No, the 90 degree manifold is not correct. The correct configuration for the engine would be a 3/4" NTP threaded hole in the engine block and no mounting studs.

The hole that exists in your block is almost (within a few thousandths) of the correct size for a 1/2" NTP tap. In your case, and what many people have done (including myself), is to tap the existing hole using a 1/2" NTP pipe tap, inserted a 1/2" pipe nipple, add a 1/2" to 3/4" 90 degree elbow, and finished the rest of the exhaust system with the correct 3/4" pipe and 45 degree elbow. The reduction of the exhaust port from 3/4" to 1/2" at the block manifold is insignificant to the engine's performance.

The remaining stud holes are sized 1/4-20 I believe, and the normal procedure is to insert two bolts, cut them flush to the flange face, sealing the two holes. They should not be left unplugged if you decide to do the 1/2" NTP tap routine.

[71_Bronco 1,072]

Pictures are always worth a thousand words ...

No, the 90 degree manifold is not correct. The correct configuration for the engine would be a 3/4" NTP threaded hole in the engine block and no mounting studs.

The hole that exists in your block is almost (within a few thousandths) of the correct size for a 1/2" NTP tap. In your case, and what many people have done (including myself), is to tap the existing hole using a 1/2" NTP pipe tap, inserted a 1/2" pipe nipple, add a 1/2" to 3/4" 90 degree elbow, and finished the rest of the exhaust system with the correct 3/4" pipe and 45 degree elbow. The reduction of the exhaust port from 3/4" to 1/2" at the block manifold is insignificant to the engine's performance.

The remaining stud holes are sized 1/4-20 I believe, and the normal procedure is to insert two bolts, cut them flush to the flange face, sealing the two holes. They should not be left unplugged if you decide to do the 1/2" NTP tap routine.

Thanks again!

I am probably going to go with the manifold that I have on it for 2 reasons. 1 will be so that when I do tap, I will be tapping the maifold, and not the block, and if I screw up (no pun intended), then it will be a junk manifold, not a whole junk motor. Number 2 is that should I need to take off the exhaust for any reason, it will be allot easier to undo the two nuts and pull it off, leaving the motor in place. Just makes it easier in my opinion.

When I do eventually get the correct air filter (the oil bath one), and the correct pull starter (if the planets ever align lol), then I will tap the block and do away with the manifold. But for now, I like it and I think it will look fine on there once it is all cleaned & painted.

[MikesRJ 552]

I do not believe the manifold will clear the frame's upright. You really need to read that article I posted. Most everything you've asked so far is covered within its pages.

[71_Bronco 1,072]

There's 2 pics of my engine tag. The number that you thought was my spec number (2739A) is kinda just floating there.

I will read your thread right now actually, was kinda busy this evening and am finally sitting down.

EDIT: Nope, looks like I won't be reading that thread tonight. It is giving me an error and not letting me access it due to an IP Address issue. I will try to read it while I am at work tomorrow and hopefully I can get info there.

Thanks

[MikesRJ 552]

Have no idea why the "7C1" is there, but the spec is certainly 2739A. You should be fine on the MWH site now as well.

[71_Bronco 1,072]

Have no idea why the "7C1" is there, but the spec is certainly 2739A. You should be fine on the MWH site now as well.

Thanks Mike. I have been reading it little by little on my phone and at work. Allot of great info in there.

Thanks allot!