C-81 Kohler 8hp - engine keeps cutting out

[gwest_ca-(File Mod) 10,489]

7 minutes ago, oldredrider said:

Garry, good catch on the shorter tappet.  I ALMOST changed out cams on a 953 engine to put in the ACR cam, but my gut said "leave it original". I didn't even consider tappet length,  although it might have been ok with the adjustable valves on the big block.

Or maybe not!

I added to the last line in the previous post.

 

Garry

[Erby 15]

Working back through all the great input from everyone, just want to now clarify what i think i've understood

First - the camshaft replacement that we have bought is the correct part number for our Kohler 30452 engine but there are two versions of this part - 

A - Automatic compression release version of the A-230155-S with non-adjustable tappets - this is (i think) what we have originally and that has broken (A on the photo attached)

B - Earlier version, automatic spark advance version of the A-230155-S with adjustable tappets - this is what we have bought from the guy in Kentucky? (B on the photo)

 

Secondly - the part we have bought will not fit/work in our engine? (anyone want it?  )

If the part number isn't correct, does anyone know what it should be? And Stevasaurus i think you said you have one that is the same as our broken one that i could buy?

I've measured the lobes on each model. The lobe lift (from the top of the shaft to the top of the lobe) is almost the same but the lobe dimensions for the exhaust are different - our model is bigger at 32mm (and bigger than the inlet on our model) while on the earlier version (purchased to replace) the lobes (inlet and exhaust) are 28mm 

[stevasaurus 22,229]

Erby...those measurements would make sense...I think the earlier  spark advance version would have had the same length tappets, while the newer ACR has the shorter tappet compared to the intake tappet.  I still want to wait for @prondzy to weigh in, but I am thinking the 7hp and the 8hp Kohlers are the same block.  I'm thinking that the one you bought from Kentucky would work, but you may need to get a new tappet and/or a new exhaust valve.

   I did look at the extra cam shaft that I have today.  I wanted to make sure it was like the picture that I sent you in this thread.  It is still in my spare engine, but would only take a few minutes to pull out.  The extra one I have is the ACR version...like the one that you originally had.  I don't think the 7hp and 8hp engines had adjustable tappets...ever.  Those are in the larger K series engines.  Like Mike said before, that cam you bought has a piece that can be 180 degrees off and it looks like it advances the spark of the points.  It sure looks like the same cam to me, except for the ACR and the ASA difference.

   Where did your cam shaft break??

[prondzy 3,867]

@stevasaurus, after reading everything im up to speed. @Erby sorry to hear about your dilemma. I will say that the k161 cam will probably fit and a person could  make it work if they had the correct valves and tappets from the k161 motor. However having said that, MY BEST JUDGEMENT is not to use the k161 camshaft. I would look for another k181 camshaft or even check your local craigslist for a k181 motor sometimes you can score a donor motor for the same price as the part your looking for. The cost of a new camshaft will be far better than the headache from trying to make the 2 peice camshaft  work. my  . Steve ironically we have found out that the internal castings of the 7hp and 8hp motors dont match this is because the 8hp has a longer stroke and will strike the lower skirt casting of the cylinder bore in a 7hp block.

[stevasaurus 22,229]

Thanks Mike. 

 

Erby, I like that thread you found...here is the link...

 

I thought I would add the link here for the benefit of others that may follow. 

   If you decide to try the Kentucky cam, you should only need another tappet like on your input cam.  With the cam being longer, the valve you have should work after being ground to the proper length. 

 

[Erby 15]

http://yes this is exactly the same as my engine  Hi Stevasaurus thanks for your interest in my dilemma I have read through this detailed procedure but not knowing very much about Kohler Engines and their different types I cannot find any reference to the camshaft . I will remove my camshaft and compare diamentions tomorrow and contact you with what I find.

[Erby 15]

Hi Steven It s back on the road, I eventually got it back together and it started 2nd turn of the key made a small adjustment to the governor and its now has so much power I am only using 1/4 throttle .thanks again to you and  all the other guys who made suggestions to try and solve my problems, all the best for the new year hope every thing goes well with your new President.      

[stevasaurus 22,229]

Thanks for letting me know it all worked out for you.  I was glad to help.