B&S horizontal shaft opposed twin

[Keith 21]

I don't think this 18 HP B&S horizontal shaft opposed twin cylinder motor was ever used in a WHeel Horse tractor.   This opposed twin seems to have some fans, although it is relatively uncommon.  It was used with some garden tracors which also could have been equipped with an Onan.    Does anyone know specs on this motor?  Shaft dimensions,  shaft height from bottom of motor etc?    There might be more than one series of these, I have no clue.    Some where used on the Sears GT-18 tractor with six speed manual.   If so, I think rebuild parts are available at reasonable costs.  There might be a 16 HP version as well.  This motor seems to have less valve seat problems than some Onans.

 

Tim  

[Fordiesel69 267]

Is this a question?

 

Work Horse such as the GT-1600/GT1800 and also the GT1642/GT1848 had these motors.  The 16HP version is a 40 cubic inch, and the 18HP was a 42 cubic inch.

 

They do have valve seat problems, but not to the extent of the onan.  Some of the twins were aluminum bore versions, and would wear out long before the seats loosened up.

 

With proper maint, they can last as long as a one lung K-Series Kohler.  They run smooth, have lots of power, but use tons of fuel. 

 

In operating my GT-1642, the engine never has to labor to plow or mow.  The onan's are equiped on the upper end tractors and their hydro tranny in conjunction with the 60" deck will make the onan really work hard.  When working hard, the EGT;s go up and therefor heat the block area around the valve seat.  So my question is.......if you mow with an onan with a 42" deck and it never had to labor, will it pop valve seats? 

[boovuc 1,090]

The answer to that question is, yes it will but the odds of it happening are less than with a hard working, hotter 60" deck fitted Onan but that is just part of the equation!

It still comes down to many factors. Here are a few.......A 42 inch 520 with dull blades mowing 8 inch grass at 3PM on a 98 degree day at 70% humidity will work harder than the guy who uses his 60" sharp blade mower cutting 4 inch grass an hour before dark on the same type day.

Also, if you have an acre or more, you'll run your 42" deck Onan twice as long mowing the same grass as the 60 inch deck guy does. More hours on the machine verses less hours with a bigger deck. See what I mean?

Not all Onan's pop valve seats. Not all K series Kohlers run forever without a problem. Not all MTD tractors are junk! No! Strike that last statement but you get my point. Do the maintenance as required and go the extra steps to keep the flywheel screen clean and the tins and fins blown out, change the oil on a very regular basis, keep the plugs clean, change the filters and keep the carb and the engine tuned and you can use your tractor without paranoid thoughts of a valve seat letting loose.

 

(Says the guy with a spare P220 on his bench)!!!!!

[Keith 21]

This Briggs twin is a 422447.  It is a smooth runner.  I have not seen much information on them.

[Jeff-C175 7,203]

I can attest to them being gas guzzlers!  I've got one on a MONSTER pressure washer.  (yes, you read that right, a pressure washer.)  I run it at constant 2800 RPM and I think it uses at least a gallon an hour.  Runs great though!