RJ Hamner 997 #1 Posted May 15, 2017 The good news: Finally found a K91 for my Suburban The not so good news: The exhaust port is not threaded The parts book lists a "spacer" part # 220819. I thought about getting one and get it threaded. I thought the idea had merit but.......discontinued part. Has anyone found a "fix" ie connector welded to a flange???????? I am open to ideas Thanks Bob Share this post Link to post Share on other sites
ACman 7,528 #2 Posted May 15, 2017 You could go the flange route or tap it with a 1/2" N.P.T . If if your not comfortable with this a good machine shop could do this and even open it up to 3/4" like the original blocks had . Use the search box ... try pipe tap exhaust port . Good luck ! 2 Share this post Link to post Share on other sites
Achto 26,583 #3 Posted May 15, 2017 Some have tapped the hole to 1/2"npt then used a bell adapter to go to 3/4"npt. The restriction of the 1/2"npt threads will not hamper the performance of the engine. 3 Share this post Link to post Share on other sites
WHX?? 46,828 #4 Posted May 15, 2017 (edited) Put up a pic of that exhaust port I have a couple of ideas to run by you but would need to see if it would work. Measure the id of it too. Edited May 15, 2017 by WHX11 2 Share this post Link to post Share on other sites
Racinbob 10,297 #5 Posted May 15, 2017 The id on my K91 was spot on for a 1/2: NPT. It actually taps very easily. I ran a taper tap in as far as I could then followed up with a bottom tap to remove some of the taper allowing the the threads to run in deeper. I immediately went to 3/4". As Achto said, the little bit of restriction won't hurt a thing. BTW, make sure you stuff a oily rag in the port first. It will help keep the chips out and drag some with it when you pull it out. Make sure every chip is cleaned out. 4 Share this post Link to post Share on other sites
RJ Hamner 997 #6 Posted May 15, 2017 I was having my afternoon cup of coffee and ran across a Briggs and Stratton "muffler adapter" part # 690776 (amazon/Jacks Small Engine) Anybody ever tried one of these on the non-Wheel Horse Kohler K91??? Granted its not too expensive and probably returnable, but thought I'd ask before I hit the "add to cart" button Share this post Link to post Share on other sites
Racinbob 10,297 #7 Posted May 15, 2017 It would be interesting to see if it would work. I'm wondering about the hole spacing and also if it would extend out a bit far for the support at the steering tower. Share this post Link to post Share on other sites
RJ Hamner 997 #8 Posted May 15, 2017 I guess if the elbow didn't tighten down far enough a fella could always shorten the nipple 1 Share this post Link to post Share on other sites
953 nut 51,802 #9 Posted May 15, 2017 1 hour ago, RJ Hamner said: I guess if the elbow didn't tighten down far enough a fella could always shorten the nipple You could use a steel electrical conduit lock nut to tighten the elbow in place. Buy it at an electrical supply house, not the bog box junk. https://www.mscdirect.com/browse/tnpla/54061304?cid=ppc-google-New+-+Lighting+%26+Electrical+-+PLA_sk69grBlc___164124449207_c_S&mkwid=sk69grBlc|dc&pcrid=1641244 3 Share this post Link to post Share on other sites
Walleye 28 #10 Posted May 17, 2017 @RJ Hamner - I am looking for a flange to NPT adapter, for the same scenario. I decided to grab a piece of plate, cut to fit, and weld a pipe nipple to it. Maybe I'll make one for you. On 5/15/2017 at 11:30 AM, ACman said: You could go the flange route or tap it with a 1/2" N.P.T . If if your not comfortable with this a good machine shop could do this and even open it up to 3/4" like the original blocks had . In the research I have done, there is not sufficient material around the exhaust port to tap a flanged K90/K91 block to 3/4" NPT. The blocks are different castings and there is not enough material around the exhaust port for a 3/4" NPT to be drilled and tapped on a flanged block. Highly recommended to NOT go 3/4" NPT, and instead go 1/2" NPT. 1 Share this post Link to post Share on other sites
Racinbob 10,297 #11 Posted May 17, 2017 At least that's what it looked like on my block. Going to 3/4" would have gotten into the stud holes. I fretted over the exhaust port for some time. I had never tapped one out and was hesitant fearing I would ruin the block.. I pondered flanges, searched the internet and paced to and fro the garage looking at it. Once I got the nerve up I had to chuckle at how easily it tapped. My tap wrench wouldn't hold that size tap so I made one from angle iron to allow me to get even pressure on two sides of the tap. It just felt better doing that rather than using a wrench on it. 1 Share this post Link to post Share on other sites
RJ Hamner 997 #12 Posted May 17, 2017 Well the B&S muffler adapter arrived in the mail today. It does not look like it will work. The studs on the B&S are farther apart. Ya pays your money, ya takes your chances. So.......Mr. Walleye what is the going rate for a custom crafted exhaust thingee??? Share this post Link to post Share on other sites