Valve Adjustments - Sooner than you think?

[DV0993]

I just spent some time checking the valve clearances on my low hour outdoor power equipment.

A GXV160 powered Honda Mower and a GX25 powered blower and trimmer.

The mower has an hour meter - it is at a mere 8 hours - The others do not.

The point of this thread - All valves were out of spec with very low hours - Is this something that could occur due to the break in process? Perhaps subsequent valve adjustments won't be as bad?

 

[PontiacHO]

The valves weren’t set right when new. Just enough effort at factory to crank, run, and sale.

 

[Trav]

I just spent some time checking the valve clearances on my low hour outdoor power equipment.

A GXV160 powered Honda Mower and a GX25 powered blower and trimmer.

The mower has an hour meter - it is at a mere 8 hours - The others do not.

The point of this thread - All valves were out of spec with very low hours - Is this something that could occur due to the break in process? Perhaps subsequent valve adjustments won't be as bad?

Totally normal for most engines with adjustable valves, if they were loose there was a little cam wear, if tight the valve seats receded a little, both are normal. After a couple of adjustments it will stabilize.

 

[Revving2Redline]

Totally normal for most engines with adjustable valves, if they were loose there was a little cam wear, if tight the valve seats receded a little, both are normal. After a couple of adjustments it will stabilize.

On to a different note...is it possible that when I get my valves adjusted on my Accord that for a time, mileage seems a bit lower? It was done during the winter months so I guess cold weather and fuel change could cause? It's better to be slightly loose vs tight? Finally, what's the reason that my mad scientist writes up his findings that only one or two valves ever needed any adjustments? Thanks

 

[nwjones18]

On the flip side I checked the valves on my 23hp Briggs at 120hrs and they were in spec. no adjustment required.

 

[Trav]

You will definitely see a slight difference with cold weather blended fuel, I am seeing 0.6-0.9 MPG lower, not having a choke the injectors run richer hence more fuel being delivered when cold for the same effect. If the valve spec has a range between x-y I always go for the middle of the range otherwise to spec. As long as the clearance in in range there is no chance of burning a valve due to adjustment.
With aluminum head(s) valve clearance actually increases as the engine gets to operating temp whereas on an iron head it decreases, on these it is better to go a little on the loose side. This is worth reading..

https://www.motortrend.com/how-to/ctrp-1012-setting-valve-lash/