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Idle Speed of a 10HP Briggs


RHA

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Hi Everbody, Today I installed a Tinytach on my B-110:).When I check the idle it was idling at 530 rpm,sounds right to me!! I read the spec sheets and it tells me to set it at 1200 RPM?????It just seems to hi!! What do you guys think???? Thanks Richard
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At 530rpm there is really no oil circulation and the cooling air is also alot slower, these are two things you don't want your engine to do without.
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With the points set at .020 I have never got a Kohler or Briggs for that matter to idle THAT low. Unless you have the timing very retartded.
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quote:
Originally posted by MikeES
With the points set at .020 I have never got a Kohler or Briggs for that matter to idle THAT low. Unless you have the timing very retartded.
I've idled many of my CI Briggs slow enough to cont the rpm's from the front crank pulley and never had any problem. But I don't think They were retarded as much as I normally am.B):D:o)
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This is kinda odd this came up today. I just started the 10HP I had on the porch and it seemed to be running fast. Maybe it was in spec? I guess this proves that without an instrument we don't really know. I gotta get one of those tach things. where do you get them and what roughly, do they cost?
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One more thing guys,this tractor has been in my family since it was new.I just can't remember ever hearing it idle that hi!!!!!!
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1,200 does sound high, but I believe it needs it for adequate cooling. I like how they sound down about 700 RPM myself, but I don't do it. I never thought about the "splash" lube system being inadequate at a lower RPM--does anyone know this for sure (no offense)? I figured a "splash" system would be safer running too low than would a pressurized system, but now that you guys mention it, you've got me wondering if "inadequate splash" is also a reason for the 1,200 RPM floor. If you think 1,200 sounds too frantic, try setting it at the aluminum engine speed of 1,800. Hey! Thinking outloud: since there are both aluminum and cast iron splash engines, and the cast can lubricate down to 1,200 RPM, that would seem to imply that, at least from 1,200 to 1,800 RPM, the sole concern is adequate cooling airflow, not splash problems (above 1,200 RPM, that is). I use a "vibratach", which is discussed here a lot (do a search?). Mine came in a Briggs box, (I think I got it off the internet) and was $18.00 a few years ago. I like it and it seems very accurate. It uses a vibrating wire and a calibrated scale to give you the reading. Peter
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Anyone interested in a vibratach might want to check the prices at http://www.jackssmallengines.com/searchdb.cfm Tecumseh part # 670156 is $10.61 while the Briggs part # 19200 is just about twice as much for the same tach.
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I keep a long bottle brush handy to clean out the bottom screan on my mowers. It can be reached from the bottom with a deck on and throught the side, this will keep the air flowing. Yes i love the sound of a old CI putt putt at about 400 to 500. And I have a few carbs set that low but i never try to make a habit of letting it runn that low for any long peirod. Tinytachs are great but a vibera tach is a must. I have a tendecy to leave the tinytach mounted on the mower i use the most. And hate to remove it to check other motors.
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I guess I really cant see what the big deal with having your idle set really low. I mean who would let their tractor idle for hours? All of mine are set low, some seem like they could die at anytime. when I have mine idle, it's just for a minute or so. If longer, I shut if off. Whats the problem with that? Elon
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I'm with you on that Elon. I've not had any problems and I like them to idle slow also, although my limited experience is mostly with Kohlers.
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Been told before not to idle them too slow, and I rarely run them on a real slow idle, but I always feel like I don't have the carb set quite right if i can't bump the throttle from 350 -400 rpm to wide open and have it jump up without a bleep. Love the sound of a cast iron Briggs at around 400
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  • 3 weeks later...
I have to agree I've never herd of anyone wrecking a motor from under reving, I love to here a one lunger run low as possible,and I really don't think anybody would let a motor like that for long That's just my two cents!
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I have a horizontal 8hp CI briggs that just doesnt sound any better unless it's loping down around 3-400. Although I only run at that speed for short time periods it seems to be the general concensus that there is no sound like it. Glad i'm not the only one that does this just to hear that pop pop pop. I went so far with mine as to add a 180 dollar knock off Harley Davidson pipe with the baffel still in place. Gives it a deep throaty sound when idling and a pleasing low tone growel when at higher rpm's. Sean
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quote:
Originally posted by FastPaul
I have to agree I've never herd of anyone wrecking a motor from under reving, I love to here a one lunger run low as possible,and I really don't think anybody would let a motor like that for long That's just my two cents!
I have. A friend of mine stopped to look at a nice looking clean mower a guy had for sale in town once. He was using at the time he stopped and was mowing with it on the lowest throttle setting. Apparrently he always mowed with it like that since new. My friend didnt take it for that reason but knew they guy who eventually did. He started mowing with it runnning it on high throttle like its supposed to be and the engine didn't last two weeks. When it came apart he noticed there were signs it hadnt been getting lubricated enough and there were signs of heat stress damage. So There must be some truth to the point of little lubrication and cooling at low RPMs.
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One reason I set idle low is when I first fire it up at 10 degrees out, that oil is like molasess. I think the danger of reving to 1200 with thick oil would out weigh running at 450 for a minute or two. I won't throttle up till I am convinced the oil has loosened up some. Just my opinion.
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I'll agree with Rich. In any engine, whether a lawnmower, 2-cycle, or even an automobile. I have seen engines in cars revved at startup, and have had to buy the customer a short block because there was no way to patch the hole that the rod went through! ( Occasionally, I rebuild an antique automobile engine) Lawnmowers are the same. They have limited lubrication, anyway, and need to run a bit at idle to loosen the oil and get it on the parts it should be on. That is why I hate the late model carbs on most lawnmowers, prefer a seperate choke from the throttle, and have replaced most new ones on my own equipment with older versions. I think this new carb is a way to sell engines, anyway, from over revving at startup. A humble opinion, but my opinion.
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I have a log splitter with an 8 horse Tecumseh. I always hated the way the choke position was past full throttle. It had to start at a faster rpm than my liking. In cold weather, when I use it of course, I had to jockey it back and forth at a lot faster rpm than I would like it to keep it running until it warmed up. I nipped the choke tab off of the throttle and mounted a separate choke cable. Now I can start it at a lower speed and keep it running until it warms up a little.
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