hotrodtractor Posted April 21, 2011 Posted April 21, 2011 My 7010 toy Harley tractor has the 243431 briggs 10hp. Engine is mint and hopped up apparently. As I changed the rear pulley to 3.5" she's a little racer in 3rd gear yet nice and slow in 1st. My issue is that shifting sucks so I often use the throttle to regulate speed, which work very effectively. My concern is I often putt around (not mowing or working)at low rpm's even near idle. I know air cooled engines need air to cool and to move air one needs rpm's. For example the manuals state to use 3/4 to full throttle when mowing. Am I shortening the life or mistreating the engine by operating at low RPM often? Note if going up a hill or something I would up the RPMs... but just rolling down the street in 3rd idle works well.
HubbardRA Posted April 22, 2011 Posted April 22, 2011 If the engine feels like it is being loaded, then you need to turn up the rpm for more cooling and more power. If it is totally running free just like it would be when sitting and idling, then it is probably not hurting the engine. I have a 243431 in my 716H. That is one powerful little engine for a 10 Hp. I use the chipper-shredder on it, push snow with a 48 inch blade, and have mowed with a 48 inch mower on it. The only two things on mine that are not stock is that the easy-spin bump was removed from the camshaft, and I also have a 3-bolt carb from a model 19 with a short intake on it. A very powerful little engine. I have a 16 Hp to replace it with, but the way this engine runs, I just hate to remove it. It also uses very little fuel compared to the larger ones. 1
hotrodtractor Posted April 22, 2011 Author Posted April 22, 2011 thanks Rod. I do not know much about these older engines. I have no complaints with the power either, yet I have not used it for any attachments... yet 8D. I wonder if driving on flat road in gear would be much of a load.. engine does not seem to notice. Supposedly this one is jetted and has higher compression I have no way to confirm but that is rumor on this hotrod.. not that it matters to me much. Originally I was going to pull the engine and replace with a vanguard or 10hp china diesel, but then I found out this little 243431 has a loyal following.
HubbardRA Posted April 22, 2011 Posted April 22, 2011 I don't understand re-jetting, since the main jet is adjustable on these carbs. Higher compression is usually gotten by milling material off the head to produce a smaller combustion chamber. Since most of the flathead engines only run around 6:1 from the factory, increasing compression also increases efficiency. They will make power with less throttle. With a small increase in compression, the engine will run cooler at the lower speeds, but should definitely get hotter when run at WOT with heavy loading because it is making more horsepower. I have a 14 Hp Kohler that I milled .062 off the head. That will produce nearly a full point increase in compression. It starts easier, runs much better, and appears to have a significant increase in power after the modification. From the information I could dig up about the effects of increasing compression, I calculated the performance increase to be about 1.25 Hp. We used it for tractor pulling for several years, so I can't really speak for the engine heating when operating attachments. I have used it to pull a trailer loaded with dirt, and to drag logs out of the woods and to drag telephone poles. I have never noticed it getting any warmer than any other engine I have.
MikeES Posted April 22, 2011 Posted April 22, 2011 On a M-20 with separate open exhaust pipes (pulling tractor). Changed head gasket on one side, the new gasket was slightly thinner than the old. The exhaust was definitely hotter (by feel) on the new gasket side. Changed the gasket on the other cylinder...now both sides feel about the same temperature. Can't say you could feel any difference in the air temperature coming off the heads. Did the new gaskets improve performance...really couldn't tell...the tractor wins most of the time before and after ;)
donmoore1904 Posted April 23, 2011 Posted April 23, 2011 I didn't recognize that as my tractor until I saw your signature and it is identified as such. Sweet. The 243431 is a workhorse. The guy I bought my 7010 from told me these should be routinely run at fast speeds, but I generally have not unless I am plowing heavy snow. There is quite a flow of air through the housing, and the motor never seems like it is running too hot. Enjoy the ride!
HubbardRA Posted April 24, 2011 Posted April 24, 2011 By the way, when I was tractor pulling with the 243431 engine, I would leave the starting line at 6000 rpm. That was the high governor setting that I was using so it wouldn't go any higher.:D Still using that same engine with no problems. Governor set down to 3600 now.
hotrodtractor Posted April 24, 2011 Author Posted April 24, 2011 hhmmm 6k rpm now that sounds like it would help me get even more speed from the hot rod. Combine that with the 26x12x12 tires that are not on yet and ..... hang on. Now I just got to get a tiny tac to determine what rpm I am turning now. That old one lung-er does seem to vibrate/shake a lot less at the higher rpms. I guess once I get a tac I could ask what to do to reset the govenor... pretty easy I have heard.
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