Toro Timecutter engine problems

[mwayne]

Had this engine's air cooling system clog up with grass clippings and overheat pretty bad. The pushrod holder for the intake valve failed by wearing out through the rubber grommet till the rocker arm rolled over. I thought the grommet failed due to the overheating event, but the replacement pushrod guide for the same intake valve failed again after about 15 hours of runtime, this time also breaking the rocker arm stud. So now I'm wondering if when the engine overheated and the oil cooked if the oil may have clogged up a passage that supplies oil to this area. The pushrod was completely straight so I don't think it is the problem. Bought new parts and have a couple of hours on them so far. Took off the cover after the 2 hours of running and there appeared to be oil on the guide and rocker arm so am at a loss to figure out what is happening. Does anyone have experience with this kind of issue? What is the valve clearance supposed to be? Thanks!

 

[the old grind]

I've only seen that on a Kohler. Sticking valve was the culprit, perhaps oil had coked in the guide from running the 25 'hot'. (mowing at ~90^F)

 

[mwayne]

I've only seen that on a Kohler. Sticking valve was the culprit, perhaps oil had coked in the guide from running the 25 'hot'. (mowing at ~90^F)

Thanks for the idea! The engine was running strong, if the valve was sticking I would expect to hear missing at least occasionally. Is this not the case?

 

[tomplum]

Unless the guide is migrating, I'd too say the valve was sticking.

 

[RandyT]

Valves guides on Briggs engines will migrate toward the rocker arm if overheated. Check to make sure the guide inside the spring isn't closer to the keeper on one valve than the other. Repeated sticky valve will cause the same thing but usually causes bent push rod on both the Intek and the Vanguard engines as well as other brands.

 

[Katahdin]

I have a 2005-2006 model TimeCutter Z420 with the Briggs & Stratton Intek series engine. Estimate maybe 750 hours in 14 years, I've never had an engine problem.

 

[mwayne]

tomplum and RANDYT, thanks for the information. Going forward I'll know what to look for and be able to put together a plan.

 

[mwayne]

I have a 2005-2006 model TimeCutter Z420 with the Briggs & Stratton Intek series engine. Estimate maybe 750 hours in 14 years, I've never had an engine problem.

Someone (not me!) ran this mower through dried grass multiple times in multiple directions. This ground up the particles small enough to get past the screen and in the fins in addition to clogging up the screen. It was readily apparent by the smell of it's oil that an overheating event had occurred.

 

[mwayne]

As a follow-up to the earlier problem:
I replaced the rocker arm and pushrod guides again but this time, about once every hour of runtime I inspected and adjusted the valve lash. Apparently there is an extensive break in time for the rocker arm as resetting the lash was required for the first few hours of operation. Taryl from youtube recommended .004" in one of his videos and that is what I used. Put about 15 hours on the engine since the last adjustment and all is well.

 

[tomplum]

:thumbsup: