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Universal M25XP not starting...air in system?

smosh

.
Jul 5, 2014
7
Tartan 30 27 Casco Bay
Hello all -

I'm crossposting from Another Forum...but I'm hoping one of you can help....
-------

I've searched all over, found and followed a bunch of advice on bleeding, but still can't start, and I want to focus on next steps before running down my battery.

Let's set the scene:

1990 Catalina 30 is new to me. Delivered her this weekend from Cape Cod to Maine. Motored hours and hours and hours: no problem (sailed when we could...really!)

Left Sunday morning about 9:30....lots of motoring. Make it all the way to the marina we were shooting for at about 3am. A hundred meters from the dock, the motor bogs down, eventually dies. It starts back up for a few turns of the prop.

We eventually spin ourselves around with momentum and the current so I can leap to the dock with a line and pull her in. (at some point in there I dump in 2 fresh gallons of diesel...friend thought we might be out of fuel.)

I start working the problem immediately. The previous owner kindly left aboard a box of fuel filters, oil filters, filter wrenches, and changing supplies. I changed the Racor and the secondary fuel filter.

No start. Ok, bleed. To the internet! Read many threads. Opened the knurled nut. Bubbles appear. I didn't have a 14mm socket, and I can't fit a wrench in there to bleed the secondary filter. I check the Racor - there's fuel in the bowl. I carefully drop the secondary filter...it's almost full of fuel, but not full. I get a ride home to gather tools and come back to attack again.

I crack the secondary filter's nut. Bubbles, eventually what I think is a drip. Still no start. I read a GREAT tip about turning the fuel pump on and off (the master ON/OFF switch right across from the motor..genius). I cover the area in soak pads, then open each bleeder in order. Looks like full fuel flow...pretty much a gusher. Cleanup was fun.

I tried cranking again. No start.

I will note that occasionally the motor seem like it wants to start..coughs, strong smell of exhaust...

So that's where I'm at. Boat tied to a face dock of not-my-marina, motor not starting...I need to get it off of there and to my club mooring.

Most things I read indicate you don't need to bleed at the injectors....as long as you are bleeding the knurl nut.

What do you think?

Thanks!
 
Sep 25, 2008
6,271
Alden 50 Sarasota, Florida
Given you ran out of fuel apparently before this started, it’s quite possible you sucked enough gunk into the system and enough got through the filters clogging the injectors. It’s a simple matter to bleed them but before doing that, I’d remove the pick-up tube in the tank to ensure it’s not clogged. While it’s open, check the bottom of the tank by sucking fuel at the bottom and look at it to see how much crud is there. Finally, bleed at each injector. If that doesn’t work and your engine has an air filter, remove it to see if you have an air problem.

Diesels only need air and fuel so it must be one.
 

smosh

.
Jul 5, 2014
7
Tartan 30 27 Casco Bay
Given you ran out of fuel apparently before this started, it’s quite possible you sucked enough gunk into the system and enough got through the filters clogging the injectors. It’s a simple matter to bleed them but before doing that, I’d remove the pick-up tube in the tank to ensure it’s not clogged. While it’s open, check the bottom of the tank by sucking fuel at the bottom and look at it to see how much crud is there. Finally, bleed at each injector. If that doesn’t work and your engine has an air filter, remove it to see if you have an air problem.

Diesels only need air and fuel so it must be one.
Thanks for the reply, Don. I don't think it ran out of fuel - in the suddenness of the moment, and with the 2g in hand, we dumped it in. Based on our consumption the previous day, the math doesn't work out to us running out of fuel. There's probably about a half tank in there....agreeing with the gauge.

There was some grit in the Racor, but nothing growth-like. The filters that were on there (from last season) probably only had about 30 hours on them. As I said, she ran fine up until that point. Maybe just finally sucked up the wrong thing.

Thanks for pointing out the pickup tube...that led me to posts about messed-up pickup tubes in C30s.
 
Feb 26, 2004
21,906
Catalina 34 224 Maple Bay, BC, Canada
Then there's always this, too:


You've begun a reasonably systematic process. Stay with it. Good luck.
 
Jan 7, 2011
2,832
Oday 322 East Chicago, IN
A few thoughts...

1) Be careful cranking away on the engine, with the water intake open and the impeller in the pump as you could water-lock (hydro-lock) your engine...essentially getting water into a cylinder and then bending a rod or worse...water won’t compress like air...

2) You mention bleeding fuel filters, but did you bleed at the injectors? I don’t have a MX25, so maybe those are not places to bleed on that engine, but just asking. Are you seeing fuel at the injectors ? Won’t tell you if the injectors are plugged, but one step closer to finding the issue. I saw aYoutube video of a guy working on his Yanmar 2GM20 and he pulled an injector, reconnected the fuel line, and then turned the engine over (by hand) to see of the fuel was spraying out...can be dangerous, but he did it and found one injector was plugged.

3) As Don said, you could have sucked junk into the fuel pickup tube and it is plugged. Maybe not since you said that you have fuel in the Racor, but we don’t know for sure...something to check.

It seems fuel related since the engine was running until it bogged down and died....

Greg
 

smosh

.
Jul 5, 2014
7
Tartan 30 27 Casco Bay
A few thoughts...

1) Be careful cranking away on the engine, with the water intake open and the impeller in the pump as you could water-lock (hydro-lock) your engine...essentially getting water into a cylinder and then bending a rod or worse...water won’t compress like air...

2) You mention bleeding fuel filters, but did you bleed at the injectors? I don’t have a MX25, so maybe those are not places to bleed on that engine, but just asking. Are you seeing fuel at the injectors ? Won’t tell you if the injectors are plugged, but one step closer to finding the issue. I saw aYoutube video of a guy working on his Yanmar 2GM20 and he pulled an injector, reconnected the fuel line, and then turned the engine over (by hand) to see of the fuel was spraying out...can be dangerous, but he did it and found one injector was plugged.

3) As Don said, you could have sucked junk into the fuel pickup tube and it is plugged. Maybe not since you said that you have fuel in the Racor, but we don’t know for sure...something to check.

It seems fuel related since the engine was running until it bogged down and died....

Greg
thanks, Greg.

Yup, closed the raw water seacock. My reading has indicated that on this Universal model I don't -need- to bleed the injectors individually...that as long as the 'knurled nut' is free flowing (it's inline before the distribution to the three fuel pipes) then it's bled. BUT, it won't hurt to bleed them, and I will.

There is plenty of fuel in the filters, so I wouldn't think it -would- be the intake, but worth it to have a look. As will be the ball valve on the Racor.

I found the tank and outflow to the motor...have to figure out how to best take out the intake pipe. Do not want to break anything. I'm thinking hose, then shutoff valve, then elbow.

It really does have to be fuel.
 

arf145

.
Nov 4, 2010
431
Beneteau 331 Deale, MD
It sure sounds like you ran out of fuel, considering that you saw bubbles when you were bleeding. Air got in there somehow! Seeing fuel in the filters doesn't mean there isn't air in the system somewhere.
 

RitSim

.
Jan 29, 2018
237
Beneteau 411 Branford
I have had a similar issue with starting that engine. After trying all methods, finally removed the injectors and reconnected to high pressure fuel lines. Ran starter till I saw fuel spray. You will need replacement copper washers at the bottom of the injector. Engine started right up.

good luck
 
Feb 26, 2004
21,906
Catalina 34 224 Maple Bay, BC, Canada
I answered this same question on CF.com:

I have had an M25 for 24 years and help administer the C34 website as Secretary of the Association.


We have extensive documentation of M25 series engines. Most all C34s were delivered with M25 series engines up to the introduction of the Mark II boats in the mid-90s when they switched to the four cylinder M35 engines. That's over 1,000 of these engines in our boats.


In ALL my years with this boat and our active C34 forum, there has NEVER been a need for "cracking the injectors." Please reconsider this, because that is what the knurled knob does.


I installed a glow plug solenoid very early in my ownership (bought in 1998).


There is great merit in addressing this as a glow plug issue. I recommend you follow this up. Either that or you have an air leak in your fuel delivery system.


Good luck.


There is a wealth of knowledge about these engines on our C34 site:


Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too


Diesel Engine - c34.org


and


101 Topics "101" Series - Quick Links to "Popular" Topics includes "Electrical Systems 101"


and


Critical Upgrades CRITICAL UPGRADES - DO THESE OR ELSE!!!


Please don't reinvent the wheel.

PS - Also forget any input from skippers with Yanmar engines, they are well meaning but the engines are vastly different.
 
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  • Helpful
Likes: Ward H
Jan 27, 2008
2,998
ODay 35 Beaufort, NC
Check your fuel hoses, if they are old they could be cracked and leaking (I speak from experience). If your electric fuel pump is the first item in the system after the fuel tank it could be clogged. There is a course filter in the bottom of the electric fuel pump (I'm assuming you have a cylindrical fuel pump that has a hex on the bottom). Remove the bottom of the pump with a wrench and see if the filter is clogged. You can get replacement filters at auto supply stores. You can likely flush it out with fresh fuel to clean it enough to get you going again. The pump should be after your primary Racor so the fuel is filtered first before entering the pump. Re-plumb this when you get a chance if not already done. Fuel contamination is like slime so it is easy to clog up filters, remove the line from the racor and pump some fuel in a ziploc bag or mason jar and look at it. If it is cloudy and milky looking you have bad fuel and need to polish or dispose of it. As you use the fuel in your tank the contamination concentration in the remaining fuel increases. Also check the o-seal on your fuel fill cap. If it is old you may have had water leak into the tank. Another thing to consider is your vent line to the tank. If clogged you may be getting vacuum in the tank. Good luck and let us know what you find. Here's a picture of the kind of fuel pump I'm talking about. These were common on our M25 installations from the 1980's,
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