Engine Not Producing Full Power

[scgunner]

MQ,

While Ken's got the right idea, that being to look for something that was disturbed by the mechanic. It's hard to see how working on the cooling system would have an effect on your RPM unless something was obviously damaged. From the video it doesn't look like that was what happened.

So maybe you should approach this from another angle. From the video the motor seems to be running great but with the throttle maxed only delivering about 2/3 RPM. It sounds like the motor is only getting about 2/3 of it's fuel requirement. Dave may be onto something, how old is your fuel pump is it the original?

FYI, it's not the gear case cover, that's usually found at the back of the motor. Depending on the type of motor it's usually referred to as the timing cover, front cover, or crankcase cover. I wasn't sure what you were talking about until I saw the video which BTW was very good.

[senorquill]

I had the exact symptom with my MK2 M35. It was the fuel pump. Replaced and has been good for 6 years. Not the same engine, but same symptom. Be sure the pump wires were not disconnected; I think Mk1 M25 may still run with a defective pump.
May not apply but worked for me. Good luck!

The pump wires were not disconnected, the fuel pump works since I can hear it clicking and it filled the water separator fuel filter up with fuel. From what I've been told, the fuel pumps basically work fully until they completely stop working.

MQ

[senorquill]

s/v Dude

This is a good example of what I have said on my soapbox so many times.  Don't eff with more than one thing at a time.  Is it the mechanic's problem with the gear cover removal/replacement or a fuel problem?
Who knows now. 

Folks learn the hard way but then others don't pay attention so they themselves will get into a pickle.

For the fuel -- DO NOT (YBYC) start removing/testing engine parts (injectors, etc.) before you or someone diagnoses the cause. 

It's MOST likely NOT something that you or the mechanic did not touch.  Components like injectors and pumps don't magically go bad when other work is done on an engine or fuel system. 
If she ran fine BEFORE, then why think that something else went bad while the boat was sitting idle?

FIRST, try running the engine with the fuel bleed valve half-open or full open.  Some owners say that their engines need to have that open.  Why? I have no clue why that would make a difference but I don't question their experience on their engine.

MOST likely if it's a fuel problem there's a vacuum leak -- which can a bugger to locate.  DO NOT (YBYC) start haphazardly replacing hoses and gaskets.  You may never discover the root cause(s.)
First -confirm whether there is a vac leak.

I have posted many times about the (IMO stoopid) way the XP has the fuel bleed set up.  It is IMPOSSIBLE to tell if you have bled the fuel and all air is out.  A convenient but near-useless setup.  (IMO) the setup should be changed as I did on my engine.
 
Remove the fuel bleed hose at the bleed knob and plug it off.
Put another hose on the bleed knob and bleed into a glass jar so that you can see the fuel condition. 
Foamy? (vac leak)
Is it clear? (inconclusive)
Strong fuel flow (pump ok)
Weak flow? (bad lift pump or plugged pump screen, or blockage in the line somewhere)

If that doesn't reveal an obvious problem, close the tank valve.  Use a cheap brake line bleeding hand pump from Harbor Freight and apply a vacuum onto the fuel line to the Injector Pump (remove it at the IP and put the hand pump there so that you are testing the entire fuel train -- from the tank to just before the IP.)
The vacuum should hold.
If not it indicates a vacuum leak.
Now to locate it.

Backpressure the fuel line from the same place -- the hose you tool off the IP. 
Or if it's easier, use the hose between the tank and Primary Filter and plug off the hose that you that took off the IP. 
Apply JUST A LITTLE air pressure, 4-5 psi, and look for a leak by spraying or brushing on a dilute dish soap mixture to locate the leak (air bubbles.)

On the mechanics' work - Unlikely but possible that something got screwed up w/the governor or speed control (you wouldn't necessarily see this just by looking at the linkages/adjustments.
Did the mechanic run the engine after doing the work (to ensure that there were no coolant leaks)? 
At what RPM?
Did she get up to temp? 
If not, get a different good diesel mechanic.

Ask the mechanic to check the speed control adjusting bolt.  That could have gotten out of adjustment.
If he doesn't know what that is, find another good diesel mechanic.  I would NOT eff with adjusting anything there (YBYC) unless you know what you are doing.

If one cyl is not producing, cracking the fuel line nut sequentially at each injector will reveal if an injector is bad. 
There will be a noticeable drop in RPM when you starve the good injectors of fuel.  The RPM won't change on the bad injector.

You might also need to bleed the fuel line at the Secondary Filter - the engine manual (TechWiki site) shows where that bleed is.  Or bleed the line to each injector (cracking the nut at each injector.)  Those two are a last resort, and are NOT typically necessary.

My guess (and Occam's Razor) says start by ruling out a fuel/vacuum leak --  but yah never know.

Good luck hunting/diagnosing and let us know 'bout each step you try.

Ken,

Thanks for the info. I only changed out the fuel filters which I have done a bunch of times, so I doubt its anything I did. I think I will attempt to talk to the mechanics first to see if they can figure it out or give me some sort of discount for the $1100 I paid them. The whole fuel issue idea was brought up early in the post and it probably has nothing to do with what's going on, since it worked perfectly fine before they removed the entire gear case. The gear case involves the entire throttle body and the speed control screw, Governor etc... I'd imagine he messed up the governor some how, because he did mention springs to me.

[KWKloeber]

If your tank is less than full, maybe topping off will help your problem, then you can suspect the fuel pump. 

...exact symptom with my MK2 M35. It was the fuel pump.

Just get a $15 fuel pump pressure/vacuum tester gauge at Horror Fright.  It checks the fuel pump (enough pressure to deliver fuel to the Injector Pump.)  But you can also check fuel flow as I first described.

While you're in there, check the screen on the Facet lift pump.  Replace if needed (not a willy-nilly replacement - a low cost and good PM item.)

I only changed out the fuel filters which I have done a bunch of times, so I doubt its anything I did.

Since it worked perfectly fine before they removed the entire gear case.

Are you saying that she ran fine after you changed filters and the only change was the gear cover?

If everybody who changes filters has never had an issue then no threads would/should exist on any forum re: related fuel system air leaks!!

The GOOD PART is that you have a running engine, so don't do anything (YBYC) to change that (like pull injectors.)   You need a running engine to diagnose the cause.  (BTW, HF has a reasonably priced injector pump test kit -- I don't know if it contains everything we needed for our IPs.)

The gear case involves the ....   Governor etc...
I'd imagine he messed up the governor some how, because he did mention springs to me.

Well not really -- the only governor part interconnecting w/ the gear cover is the START spring.  You don't get at the governor per se when changing the Gear Cover.  The speed control group is so simple that it seems to me to be an unlikely cause.  Again, have him check the speed control adjusting bolt.

Good luck!!

FYI, it's not the gear case cover, that's usually found at the back of the motor.

Actually, it's the Gear Cover (or Gear Case) (regardless whether Toad and/or Westerbeke improperly renames things otherwise.  Unlike many engines there's no timing belt or timing chain on our Kubota diesels (timing is set by shimming the IP.)  (There are timing cases on other Westerbeke engines.)  Comical yet typical that below Westerbeke calls out "timing gear" - yet there is no such part.

Everyone should occasionally study their parts manual, not just when there is a problem -- especially Kubota's original manual.  I placed them all on the wiki.  They're invaluable when describing or understanding terminology of which part is what when Universal describes something or when talking to a Kubota dealer about parts.

As long as we're being precise, note that we have an engine.  Catalinas that are repowered with an electric drive have a motor.  (Well we do also have a starter motor that cranks the diesel engine.)

[Ron Hill]

Guys : Before you go to crazy on the fuel starvation - Remember that the fuel tank is higher than the engine so fuel will syphon to the engine if those lines are clear and the fuel flows thru the RACOR and the fuel pump screen in the fuel pump!  So the starting end of the fuel flow (tank to engine) is easy to check!!

Also the M25XP only burns about .5 gal/hr, so you aren't looking for a tremendous fuel flow out of the fuel hose at the engine!!

I ran my M25XP engine for over a year - with out using the electric fuel pump!!!!

A few thoughts

[senorquill]

 Gents,

In the fuel injection there are 2 springs, these need to be removed when taking off the gear case (it attaches to something on the front). The 1st spring has 2x 90 degree angles on the end of it. If you don't connect it at the correct angle, then when you put the 2nd on, it causes the first spring to slip off. The mechanic was kind enough to research this and then fix it.

The attachment shows one of the springs, its not the M25XP in the photo, but same concept.

Engine is now going to 3400rpm at full throttle. Idles great.

MQ

[Noah]

 

[KWKloeber]

MQ

Nice. Solved.

That's great that he was "kind enough" to research and fix it!!  Super.

I'm still a little confused, the spring shown has nothing to do with the governor; only the fuel rack/stop lever which certainly would cause an issue!) and the other spring with starting (not your issue.)
I'll try to find a Service Bulletin on this and add it to the Wiki (if I can ever get access to the Wiki again!?)

[Ron Hill]

Guys : For future reference I had a similar problem (low RPM), but the gear case had NOT been removed!!  The engine had about 3500 hrs.
I finally narrowed it down to the injection pump.  I removed the injection pump (Mainsheet tech note article) and had it rebuilt (diesel truck repair that also rebuilt injectors).  End of low RPM problem!!  Read the article!! 

A few thoughts

[waughoo]

Huzzah!!  So great to have the connection made between front cover removal and injection pump.