Universal engine goes straight to highest rpms (not runaway)

[NOLA_Sailor]

Greetings, everyone.

I am the proud owner of a Cape Dory 33 (#70, 1981), “Bittersweet.” I acquired it from my cousin in 2020, and I have completed all major repairs. You may ask, What repairs? Why? Well, during Hurricane Zeta, the tidal surge kicked the stern onto the dock, and it slowly started sinking from the bow. By the time it was salvaged about 6 days later, it had sunk about two-thirds of the way. Thankfully, only the very bottom of the engine got wet.

I did search the forums, and I went through hundreds of posts, but I couldn’t find anyone talking about my situation. The closest was runaway, but every mechanic said that is not the problem.

The first priority was the engine, in case it had taken on water. The engine was thoroughly flushed, oil changed twice, and it started right up. It was not in the water at that time, so the mechanic only let it run about 25-30 seconds.

Here is my quandary: We launched the boat in June, but when we started it, the engine revved all the way to its high end (about 2900 rpm). The only way to stop it is to cut off the air flow, same as with runaway. I have been turned down by several mechanics (“We don’t work on those engines”), and five mechanics actually showed up and looked at it. They all have different answers, the prevailing one being “I don’t think I can fix it.” I think what they are trying to say is, “I don’t want to work in your hot boat, so please bother someone else.” Seriously, I think if it were November it would be fixed by now.

The fifth mechanic said that he could, indeed, fix it, but that the engine would need to be pulled and then delivered to his (presumeably cool) workshop. He said he didn’t really know for sure what was wrong, and began “blowing smoke” at me about a myriad of things.

In toto, the guesses have ranged from a bad high pressure pump that is gummed up to a stuck governor. I really need to speak to someone who has a similar engine who can talk me through this.

About the engine:

1. It is the original Atomic Universal (Kubota) 24 hp 3 cylinder engine.
2. It was rebuilt about 10 years ago but only has 54 hours on it. (They had stopped sailing it by then, so they just started it up once or twice a month for a few minutes to keep it up.)
3. When it was started over a year ago, it purred like a diesel kitten at idle speed.

I will head off some of the questions you may have:
Is the throttle stuck? No, even manipulating it at the engine in a full range of motion, the high rpms continue.
Is there diesel in the oil? No
Is the rack pin stuck? I don’t know. It looks like it is in the groove, but I don’t know if /how it is supposed to move. I can try to attach a pic.
Is the governor stuck? I don’t know. The last mechanic said that the front of the engine needed to be removed in order to see the governor. I was under the impression that it was nearer the rack pin/throttle. Can’t find it in any diagrams.
Any water intrusion? Kinda, but not from below. There was a leak in the fiberglass over the engine (now repaired) that allowed a little water to drip on the engine. You will see in the attached photo that the rack pin area has tiny bits of rust. I am inclined to use more lubricating products, BUT I haven't because I didn't want to do something that might make it worse.

Any suggestions are welcome. And if you have a breakdown graphic of the engine that includes the governor, that would be helpful.

Thanks,
Kyle

Kyle Scafide, PhD
New Orleans/Biloxi

[bottomscraper]

I suspect that engine is built based on some version of the Kubota D1005 or D1105 block.

Here is a link to a workshop manual for that block (it might be a later version):

https://media.toro.com/servicemanuals/Kubota05-E3B.pdf

Here is a link to the parts manual for the D1105 (again may be a later version):

https://www.marinedieselbasics.com/wp-c ... -Parts.pdf

[NOLA_Sailor]

Thank you very much, Rich.

Yes, the engine is similar, especially with overall design and the governor assembly. I downloaded both of the manuals for later perusal.

The rack pin in those manuals, however, is very different, so I'm still stumped. I will see if I can find some older kubota manuals.

Kyle

[mgphl52]

My first guess is a stuck governor. We had the same problem with a Yanmar 3GM30 that had been on the hard for 3+ years. I'll let you know exactly how it got fixed when I get a chance to talk with my buddy that did the trick.

[Paul D.]

I shared your story with my diesel mechanic friend as a challenge and he said most likely governor issue too.

We've the same 5424 motor but knock on wood have never had this issue. In fact, in a long motor across Lake Superior earlier this month in little to no wind, I confirmed the throttle likes to settle down to about 1,800rpm even if I set it higher. Most likely a throttle spring/cable issue. I don't know the accuracy of the tachometer, but it does seem to run well there so I let it do its thing.

[Jim Walsh]

I shared your story with my diesel mechanic friend as a challenge and he said most likely governor issue too.

We've the same 5424 motor but knock on wood have never had this issue. In fact, in a long motor across Lake Superior earlier this month in little to no wind, I confirmed the throttle likes to settle down to about 1,800rpm even if I set it higher. Most likely a throttle spring/cable issue. I don't know the accuracy of the tachometer, but it does seem to run well there so I let it do its thing.

A common solution is a throttle cable brake. It’s one of those “set it and forget it” solutions. I replaced my throttle cable in 2016. Installed this brake, made a fine tuning adjustment and it’s been fine ever since. No creep under any conditions.
https://www.fisheriessupply.com/morse-c ... les/044386

[mgphl52]

I'll let you know exactly how it got fixed when I get a chance to talk with my buddy that did the trick.

Basically, he just "fiddled" with the governor (tapping it) and we ran the engine a few more times with vise grips ready to shut close the fuel line (hose). After several iterations it worked fine. Best guess is that all of the lubrication in the governor had seeped out causing it to stick.

[eb1smith]

I am not sure if this will help, but this is from posting on another group:

Universal M-25 is a Kubota Block D-850
Universal M-25XP is " Block D-950
Universal M-30 is a " Block D-1101 & D1102
Universal M4-30 is a " Block Y-850
Universal M-35 is a " Block V-1200

--Eric

[NOLA_Sailor]

Thanks, everyone, for your ideas. I'm going to try some of the suggested resources. I honestly think that the "fiddle with it" approach would work. I'm just not sure where to fiddle.

It's not the throttle or anything to do with that, though it would make sense. We tried that first thing and eliminated it as a problem.

Also, I could reeeeeeally use a WORKSHOP manual. I have the other ones. I am going to check the Kubota resources.

Thanks, folks. And if you know a mechanic who will work in Biloxi, let me know. I have spoken to 25 mechanics, most of whom are not interested in working on a universal engine. I have shelled out about $700 to date just to have the mechanics tell me they can't/won't fix it.

(I think they don't want to work in a hot boat.)