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Discussion Starter · #1 ·
Well after the marina charging me $102 to haul the boat to try a diffrent prop and then when that did not work another $353 to trouble shoot the motor and they found nothing wrong and suggested another prop. They were claiming that the prop was to big and not allowing the governer to open up. So then I went to the internet and did a search on Universal M25 Governer and low and behold the governer is adjustable and within minutes I had the motor running up to a perfect RPM. 2500-2600 rpms and 6.2-6.3 knots into a 10 knot head wind.

Scott
 

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I am a little confused:confused:

If the governer was holding the RPM to 2100 how come the engine would free rev to 3200 RPM?;)

Just wondering for my geewizz files.:rolleyes:

1970Columbia34

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Join Date: Aug 2006
Location: Bay City, Mi
Posts: 311
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New Diesel Still with problems

Well guys still having problems with the remanufactured motor. We put in the M25xp and Martec made a 16"x16 rh prop for the boat and 2 other prop makers confirmed that would be the prop for the boat, put the boat in the water could only get about 2100 rpms and 5.o knots. so figured the prop was wrong and martec stood by there prop and made a 16"x12p rh, pulled the boat and swaped the props to find that the motor still only would hit 2100 rpms and not only go 4 knots, so now we know its not the prop. my thinking is something is up the the motor what do you guys think? motor revs up just fine when not in gear 3200+ with ease. Any ideas I am trying to locate a good diesel mechanic to look at the motor. Thanks

Scott
 

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Discussion Starter · #3 ·
Can't ansewer this I found a post on several catlina forums about having to make this adjustment on there boats since this M25 was in alot of those boats. I agree it sounds odd but it work like a charm and have confirmed my Tach reading with a photometric tach that its not running to hard. I wish I knew the answer to the diffrence between in gear and out of gear but I don't.

Universal m25 low rpm under load (FIXED !!!) - Ask All Sailors Forum

Scott
 

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Have you checked your free run RPM?

Can't ansewer this I found a post on several catlina forums about having to make this adjustment on there boats since this M25 was in alot of those boats. I agree it sounds odd but it work like a charm and have confirmed my Tach reading with a photometric tach that its not running to hard. I wish I knew the answer to the diffrence between in gear and out of gear but I don't.

Universal m25 low rpm under load (FIXED !!!) - Ask All Sailors Forum

Scott
 

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A Universal M25XP is rated at 23 hp @ 3,200 rpm intermittent. Intermittent means the engine is only designed to handle full throttle/power for no more than 10 minutes before being throttled back to cruise rpm (enough time to dodge a big ship). The stock ZF gearbox has a 2:1 ratio. I've put a lot of props on those engines and my calculator says a Universal M25XP on a 34' sailboat (probably about 26' LWL) should have a 13" diameter X 8" pitch 3 blade RH prop, or a 14" diameter X 9" 2 blade RH prop. A 16" diameter prop is too big. The engine should rev to about 3,300 rpm at full throttle in neutral (high idle), and rev to 3,100 - 3,150 rpm at full throttle, top boat speed. The sealed injection pump/governor buffer screw you're adjusting probably changes the spring tension on the rack, and it could have been tampered with, so doing adjustments on it may change things. It would be good if you marked it so you can put it back where it was. If you want to learn more about it contact a fuel injection shop that does Denso fuel injection components and see if they can explain what the screw does (I keep meaning to do that myself). Hope that helps.
 

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Discussion Starter · #7 ·
Great info, one diffrence in our situation is our gear is a 3:1 v-drive which is why is has a 16" prop on it. I have a feeling that is why it needed ot be adjusted that from the factory it had a 2:1 reduction on it.

Scott
 

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Time bandit - I am not a mechanic (maybe one could answer better), but I believe that the govenor controls fuel based on load. I think that's why it was possible for the engine to rev higher in neutral than in gear. Of course, this would be compounded if the boat was overpropped as well.
 

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Well after the marina charging me $102 to haul the boat to try a diffrent prop and then when that did not work another $353 to trouble shoot the motor and they found nothing wrong and suggested another prop. They were claiming that the prop was to big and not allowing the governer to open up. So then I went to the internet and did a search on Universal M25 Governer and low and behold the governer is adjustable and within minutes I had the motor running up to a perfect RPM. 2500-2600 rpms and 6.2-6.3 knots into a 10 knot head wind.

Scott
Awriiiiight! Dang, you're good! Feels great, doesn't it?:)
 

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What is the factory setting for the governor ahustment bolt? I am currently replacing one that was broke off in the case. I have read the servicw manual and there is no mention of the adjustment screw anywhere.
 

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Note that the Universal M25 is DIFFERENT from the M25-XPA and -XPB. The blocks are different, and they have different displacements (855cc for the M25 vs 927cc for the M25-XPx). According to the 1990 Kubota Work Shop Manual, all of these engines "minimul idle speed" is 800 RPM, and "maximum bare speed" is 3200 RPM.

Per the Universal SERVICE Manuals:
  • The factory setting limits the M25 to 3200 RPM MAX. I can find no references in the Universal manual to "Cruising" or "Idle" RPMs, but based on the Kubota manual I believe that they should be between 2100 and 2600 RPM for cruise, and 800-1000 RPM for idle. My Universal M25 idles at 800 RPM, I cruise between 2300-2600 RPM and WOT is set to 3100 RPM.
  • The factory setting limits the M25-XPA to 3200RPM MAX, Cruise should be between 2100 and 2600RPM and the idle should be 1000-1200RPM
  • The factory setting limits the M25-XPB to 3000 RPM MAX, Cruise should be between 2000 and 2500RPM and the idle should be 1000-1200RPM

The governor adjustment bolt is not labeled, and it should have a cover over it to discourage tinkering.
 
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