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HudCo 
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Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 4242
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 Topic: wd pto rpm vrs engine rpm
Posted: 13 Jun 2026 at 7:49pm |
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since the wd was overhauled back in 71 540 has allways been about half throttle i just put the stewart warner tach on my pto to see where 540 was exactly on the quaudrant and marked it it was where i have run 540 stuff since i was a kid at full throttle pto rpm is 800 so what is my engine high idle ? no one is alive that would know what was done but i think it got all 175 stuff in it its always had alot of power
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Les Kerf
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Joined: 08 May 2020
Location: Idaho
Points: 1922
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Posted: 13 Jun 2026 at 8:13pm |
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My manual shows the stock loaded RPM is 1400 at the engine and 540 RPM at the PTO. This gives a ratio of about 2.6:1 so at 800 pto RPM the engine will be about 2080.
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dfwallis
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Joined: 09 Mar 2023
Location: Texas / Indiana
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Posted: 13 Jun 2026 at 9:28pm |
Here are the conversion factors I used for my tachometer application, based on 1400RPM
Edit: Of course that's more precision than actually available on the processor, round as needed. Also assumes stock tire sizes.
float wdG1CF = 0.00178571428571428571428571428571; // Ground speed in gear 1 conversion factor (1400) float wdG2CF = 0.00271428571428571428571428571429; // Ground speed in gear 2 conversion factor float wdG3CF = 0.00357142857142857142857142857143; // Ground speed in gear 3 conversion factor float wdG4CF = 0.007; // Ground speed in gear 4 conversion factor float wdGRCF = 0.00164285714285714285714285714286; // Ground speed in gear R conversion factor float wdPCF = 0.38571428571428571428571428571429; // PTO RPM conversion factor float wdBCF = 0.9; // Belt RPM conversion factor
Edited by dfwallis - 14 Jun 2026 at 9:52am
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1952 CA13092, CA Pickup Plow, CA Cultivator, CA Two Row Planter, Dunham-Lehr GC78 Disc, Grader Blade, 3pt Fm180 Finish Mower
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DrAllis
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Joined: 12 Sep 2009
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Posted: 14 Jun 2026 at 10:40am |
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2074 RPM is what I come up with and that is a D-17 governor spring.
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HudCo
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Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 4242
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Posted: 14 Jun 2026 at 12:11pm |
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the guy at the dealership that biult that engine way back in 71 done an awesome job it still runs like new its has just had regular services ,preventive maintanance and tires the last 20 years it does nt work 50or 60 hrs a week
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Hubert (Ga)engine7
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Joined: 12 Sep 2009
Location: Jackson Cnty,GA
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Posted: 14 Jun 2026 at 2:09pm |
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When baling hay or bush hogging with Dad’s WD I always ran close to full throttle, I tried to find that sweet spot where every thing seemed to be working smoothly. I do that with my D15II also since the tach is not working and I am too cheap to buy another one. Again go full throttle and back off just a little.
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Just an old country boy saved by the grace of God.
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DiyDave
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Joined: 11 Sep 2009
Location: Gambrills, MD
Points: 56086
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Posted: 14 Jun 2026 at 3:21pm |
Non-contact laser tachs that used to cost like 3-500 dollars are now available from $10 to $40... 
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Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need!
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Les Kerf
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Joined: 08 May 2020
Location: Idaho
Points: 1922
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Posted: 14 Jun 2026 at 4:24pm |
 dfwallis wrote:
Here are the conversion factors I used for my tachometer application, based on 1400RPM
Edit: Of course that's more precision than actually available on the processor, round as needed. Also assumes stock tire sizes.
float wdG1CF = 0.00178571428571428571428571428571; // Ground speed in gear 1 conversion factor (1400) float wdG2CF = 0.00271428571428571428571428571429; // Ground speed in gear 2 conversion factor float wdG3CF = 0.00357142857142857142857142857143; // Ground speed in gear 3 conversion factor float wdG4CF = 0.007; // Ground speed in gear 4 conversion factor float wdGRCF = 0.00164285714285714285714285714286; // Ground speed in gear R conversion factor float wdPCF = 0.38571428571428571428571428571429; // PTO RPM conversion factor float wdBCF = 0.9; // Belt RPM conversion factor
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Yup! Calculate to an angstrom, measure with a micrometer, mark it with chalk and cut with a chainsaw...  |
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IBWD MIke
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Joined: 08 Apr 2012
Location: Newton Ia.
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Posted: 15 Jun 2026 at 5:46am |
[QUOTE=DiyDave]Non-contact laser tachs that used to cost like 3-500 dollars are now available from $10 to $40... [/QUOTE Yup, first one I bought only made it through one usage. Just got one last week from hobo freight, haven't used it yet, maybe today?
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HudCo
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Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 4242
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Posted: 15 Jun 2026 at 2:09pm |
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mine runs at 800 rpm full throttle wouldnt take long for the baler to blow up running that fast with all of the d17 175 engine parts in that like doc says 2074 big change fron 1400 i check the mark on the quadrat once in a while if i am working on somthing pto driven like pumps
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