Boxer 421 valve clearances

Sir ramic

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May 27, 2014
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steve martel
Hi,

My machine is going to be serviced on Saturday. New plugs, oils an filters. Am going to check the valve clearances to, but can’t find the clearances anywhere.
I was hoping to find out the valve clearances for the boxer 421.

Much appreciated
 

wandwizard

Randy Dockins
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Hi,

My machine is going to be serviced on Saturday. New plugs, oils an filters. Am going to check the valve clearances to, but can’t find the clearances anywhere.
I was hoping to find out the valve clearances for the boxer 421.

Much appreciated
If you're having this work done I'd suggest letting them check the clearances. You should have the model number of the engine and would likely have to purchase the engine manual to get that info. I purchased the manual for my old B & S engine a long time ago and I think it actually covers a number of the Vanguard engines, but yours may be different. I don't think those clearances are in the Boxxer manual, but not certain.

I'll give you what I have, but you definitely need to confirm it. Any qualified mechanic should be able to get this for you w/o a problem. My B & S manual says to check them cold with a feeler gauge and should be 0.005 inches or 0.13 mm. This is for the 21 hp that was original with my Boxxer 421. The lock nut is to be torqued to 70 in. lbs. after any adjustments.
 
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Sir ramic

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May 27, 2014
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steve martel
Hi Wandwizard,

Perfect, thank you for the information. I’ll be doing the work with a friend tomorrow.
Have no problem sorting out the clearances, just wondered if anyone had them handy.

The machine manual is pretty handy, but not a great deal on the Briggs motor in it.

Thank you for your time.
 

Sir ramic

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May 27, 2014
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steve martel
If you're having this work done I'd suggest letting them check the clearances. You should have the model number of the engine and would likely have to purchase the engine manual to get that info. I purchased the manual for my old B & S engine a long time ago and I think it actually covers a number of the Vanguard engines, but yours may be different. I don't think those clearances are in the Boxxer manual, but not certain.

I'll give you what I have, but you definitely need to confirm it. Any qualified mechanic should be able to get this for you w/o a problem. My B & S manual says to check them cold with a feeler gauge and should be 0.005 inches or 0.13 mm. This is for the 21 hp that was original with my Boxxer 421. The lock nut is to be torqued to 70 in. lbs. after any adjustments.


Yes, I’ve managed to find them. 0.005 on both the inlet and outlet.

Checked against the engine number. Tried the Briggs website the other day, but they only had a parts manual.

But got there in the end.

Thanks for your time.
 

Sir ramic

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May 27, 2014
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They are done, have checked them and they’re fine, Changed rocker gaskets. It runs really clean the engine, once started.

Machine was struggling to start, battery was draining. Checked the output from the geni an it was fine.

Only the regulator rectifier is dead. I’ll order a new one tomorrow. After the charging issue is sorted, it’ll be good to go.
 

Sir ramic

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May 27, 2014
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I tend to agree with that sentiment. If it ain't broke don't fix it. I personally wouldn't mess with it unless I knew I was having trouble.

Oil is leaking from the rocker, the rocker gaskets needed to be changed.

Whilst changing the gaskets, I wanted to check the clearances as the covers were off. The clearances were checked an fine, so other the the gasket change nothing needed to done to them.