# briggs intek 21hp ohv twin problem



## jgraham798 (Jul 9, 2009)

Hello,

I am just short of pushing this mower into the middle of the yard and setting fire to it. It's a murray rider and it's been a lemon from day one. Most of the issues have been with the mower itself but the new problem is engine related.

I was cutting my elderly neighbors yard Monday when I had a belt jump off the mowing deck. I turned the blades off and started back across the street so I could get the belt back on.

I got about 30 ft and then all of a sudden it started to run really rough and then it backfired once and has not started since then.

I am extremely puzzled this time. I did have an issue last week where one of the rocker arms slipped off a push rod and I got it back on after a visual inspection and set the clearances to 4 thousands.

The motor is 

INtek twin OHV model 406677-0344-E1

Can anyone point me in general direction to start trouble shooting?

Thanks so much for any help!


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## 30yearTech (Sep 14, 2006)

I would take another look at the valve clearance on both sides, it sounds like there may be an issue with the valves again.


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## jgraham798 (Jul 9, 2009)

30yearTech said:


> I would take another look at the valve clearance on both sides, it sounds like there may be an issue with the valves again.


Is 4 thousands the correct clearance for this engine?


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## 30yearTech (Sep 14, 2006)

jgraham798 said:


> Is 4 thousands the correct clearance for this engine?



.004" - .006" for both intake and exhaust is what is shown for your engine. Make sure you have the piston at 1/4" past TDC on the power stroke when making or checking the clearances for each cylinder.


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## justin3 (Apr 10, 2007)

Make sure both valves on both cylinders are opening fully and there is nothing obstructing movement. It may also be a good idea to replace the push rods. If they are slightly bent they can cause issues.


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## jgraham798 (Jul 9, 2009)

*got it working!*

Thanks for the help on this issue. It was the valve clearance that was causing the problems. I corrected them and now the motor runs great.
I just wished I could say that about the rest of the mower. Cut for about 30minutes after correcting the valve problem and broke a belt on the mowing deck....<sigh> This mower is making the bel manufacturers RICH!

Thanks again for all the help!!


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## jgraham798 (Jul 9, 2009)

jgraham798 said:


> Hello,
> 
> ...then all of a sudden it started to run really rough and then it backfired once and has not started since then.
> 
> ...



Still having issues with this motor. After resetting the valve clearances, the motor started fine and I ran it at full throttle for 5-10 minutes, cut it off, and restarted it fine and again it ran fine at throttle.

I went across the street to cut my neighbor's yard again and cut both the front and back (3/4 acre) w/o any probs. I turned the bladed off to go back across the street and again got the real rough idle, back fire, and then it wouldn't start. I let it sit for 2 weeks and went to check it out again and it started first time I turened the key. It idled a bit rough at first but then it straightened out. Went and cut the yard again and decidec not t oturn off the blades unti lafter I had finished my yard (1acre) as well as my neighbor's yard. Mower cut fine with no probs until I cut the blades off again. Same rough running no start situatuin as before. let it sit 2 days and it cranked again running a little rough and then strighteneing out. Sheesh! I'm not a great mechanic but I've neverr been this bumfuzzled in my life.

Can anyone give me a direction to look towards with this motor?

Thanks for all your help!

Jim


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## jgraham798 (Jul 9, 2009)

Sorry for the poor typing...I forgot to preview the message before posting


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## usmcgrunt (Sep 16, 2007)

Here is a Briggs service bulletin that describes how to properly adjust the valves.The section on overhead valve adjustment is near the bottom of the bulletin.It is critical that the valves are set 1/4" past top dead center.Your valves may be expanding from heat and loosing clearance if not adjusted according to the Briggs information.Hope this helps.


http://www.briggsandstratton.com/engines/support/frequently-asked-questions/Servicing the valves/


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## jgraham798 (Jul 9, 2009)

Thanks so much for the info. 

30year had said something about quarter past tdc but i didn't really understand it and that bulletin describes it perfectly.

I will give that a try and see what happens.

Thanks again!!!!
Jim


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