M25XP Stall out after 10 mins of smooth run

[hregan]

My first post. Thank you all for the wealth of information on this site. I'm afraid I'm an interloper, as I have a Catalina 30, not a 34. Please don't banish me – the amount I have learned from this site has been amazing! Now, the tale of my engine woes – this is long, so I tried to make it somewhat entertaining and put some questions at the end.

To summerrize the saga below:
1989 M25XP runs sweet for 10 minutes then dies.
Cracking the injector pump bleed seems to help a little (runs poorly but does't die)
I don't believe it is clogged fuel delievery
Possibly air getting in the lines from work done fixing clogged fuel delivery

I recently purchased a 1989 Catalina 30 on Georgian Bay up  in Canada. My wife and I enjoyed several overnight trips, unfortunately completely windless with no sailing, but the motor (M25XP) seemed to run fine. We probably put over 20 hours on the engine. No problems. The boat is at a dock with no services – just the dock – and we had arranged for winter storage about 6 hours by sail south. On the planned day to move her, with a brisk wind (finally!) and two children in tow we began the motor to open water. It is a 40-minute motor down a rock-strewn channel to get to open water. With the wind on the nose we began with all confidence in the motor into the chop. 20 minutes into the trip the engine began to sputter and cough. Then it died. I restarted it, but it began to sputter again, so I wheeled around 180 degrees and unfurled the genoa just as the engine died a second time. Our first sailing experience on the boat was more stressful than I would have liked, but we managed to sail her back to the dock avoiding many large granite piles and gave each other a few high fives. Rough water had stirred up crud on the tank and blocked something up I surmised – a common problem that this group confirmed (and C34.org).

So, next steps: Enlist my son the aspiring race car mechanic – not a diesel guy, but very handy with things that drink dinosaur juice; The tank has no cleanout access so I ordered one from Boyds Welding (it made it from Florida to Detroit in 3 days and has now been in border limbo for a week and a half); I pulled the pick-up line out of the tank expecting to find a clogged screen only to find someone had already removed it; I checked the metal tube and rubber end and everything was clear; I changed both the primary Racor filter (R24T) and the engine mounted secondary filter. Time to bleed and start it back up. No joy, The engine would not start. I pulled the line from the engine mounted filter – no fuel with the lift pump running. My Racor is between the electronic lift pump and the tank, so next I took the tank line and hooked it directly to the lift pump – still no fuel. I disconnected the line coming from the fuel tank at both ends and blew through it (carefully). Clogged. Another more forceful blow and out into a bucket came nasty black gunk. I have fixed it! I am a diesel god! So I thought. Everything back together the engine started and ran smoothly confirming my diesel god-like status. It had been a long day, so off home for well-deserved libations. Sadly, the saga continues...

A few days later I decided to shake off the engine fear and take her out for a single-handed anchor out. 10 minutes from the dock passing through a particularly narrow passage – sputter, sputter quit. Fack. This time the light winds were against my return and stupid me had neglected to take off the main sail cover. Trying to tack under genoa only between the red-green-there-be-dragons-markers left my mouth a little dry. Not so much of a diesel god after all I thought, once tied safely to the dock.

Round 2 (still waiting for my tank cleanout access panel): Remove the rubber pickup end to keep it out of the gunk at the bottom of the tank. Clean the check valve in the racor (thank you Stu Jackson); Add some fancy diesel additives to the tank and take 20' of fuel line and run from the lift pump to the tank fill (through the Racor), after an hour of cycling, change the Racor out with a new one (at 50 Canadian pesos a pop!). Seems to run fine, but I feel less sure of myself. A week later my son and I try a second trip to move the boat south, this time I do a few donuts in the bay by the dock and everything seems fine, off to the races. First narrow channel: sputter, sputter, quit. I think the new boat is testing me, sort of like my wife did when we first started dating.

Round 3. Replace lift pump (I may have been happy with a new filter for the old one, but getting things like that up north can be challenging and I found a whole new pump for an only mildly curse inducing 170 Canadian pesos, and I can keep the old one as a spare), changed out the secondary engine filter again (why not!). Fool me once - this time I put the engine under load tied safely at the dock. 10 minutes in – just as she is reaching operating temperature, sputter, sputter, quit. Well, at least I didn't have to sail back into the dock this time. Checked the tank vent – clear. Removed the return line, with the injector pump bleeder valve open lots of fuel flows through the return, with it closed and engine running, small drips – not sure if that's normal?

After some head scratching I was able to turn the "run great for 10 minutes then sputter, sputter, quit" into "run great for 10 minutes then  lower rpm (2400 down to 2000) with a little sputter" by opening the injector bleed valve a crack. A clue? Possibly, but it was time to go home (with a stop to pick up the extra car left at the marina we dream of getting lifted out at before the north turns into a frozen wasteland.)

My current best guess is air getting into the fuel lines. I have been at each and every connection, dripping sweat and little blood, with bad eyesight. I have probably caused an air leak. I am going to swap out all the fuel lines for new, including the return  and replace all the hose clamps with the non- perforated kind, and a bouquet of roses for boat (it could help), and finally make sure the primary and secondary filters are so tight I'll never get them off again.  I should add that flow seems good and no water or gunk in the racor bowl.

Well, if you got this far thank you. I have a few questions that I am hoping will find the eyes of a real diesel god, and a few that you mere-mortal-but-more-knowledgeable-than-me sailors could answer:

1.   Does air in the lines sound feasible?
2.   Any other suggestions or troubleshooting ideas?
4.   Is running a boat in reverse at the dock at 2400 RPM a bad thing?
5.   Is there a diesel safe version of Teflon tape, or do I need to start researching NPT thread?

Ps if it helps, I will expand on sputter, sputter, quit. The engine will be purring (as much as a diesel can I guess) at 2400. My eyes are drawn to the tach when the engine seems to start missing, then a little drop maybe 200 rpm, increasing throttle has no effect, then it starts to lope down to 1500 back up to 2000, after a few lopes, it drops to 1000 rpm, then quits.

[KWKloeber]

1.   Does air in the lines sound feasible?
2.   Any other suggestions or troubleshooting ideas?
4.   Is running a boat in reverse at the dock at 2400 RPM a bad thing?
5.   Is there a diesel safe version of Teflon tape, or do I need to start researching NPT thread?

hr,

Wow that took a lot longer to compose than clicking on the official IC30A site!

1.  Just addressed on the official IC30A forum. There's nothing wrong with interloping but You might also join us there.
https://groups.io/g/Catalina30
https://groups.io/g/Catalina30/topic/air_in_fuel_lines_on/77044056

As Stu says to C30-ers, the C-34 forum and members have the same engines as the C30. The C30 members and forum also have the same engines as, well, the C30-ers.

There's lots of great info on the "101 series" here (and simply doing a search from the main page search box.)

2. See #1.
3. (4) Inherently no, but I wouldn't for extended periods. "Your boat, your choice."
4. (5) PTFE is PTFE. If you're suspecting a leak due to poor threads you might try heavy duty (gray) pipe tape - available at a big box.

Over tightening the filter can 'eff up the gasket and cause a vac leak.

Because you can't tell if you have air in the fuel, you've identified the folly of the fuel bleed knob setup on the XP.  When I changed to the knob I specifically DID NOT use the XP way to plumb it on M-25.  I suggest you do the same (but YBYC of course.)

Which cartridge are you using, 10u not 2u I hope?

ken

[Stu Jackson]

hr,

Very good description of your issues.  I had pretty much the same problem, which is what prompted me to write the check valve post.  I also just submitted an article for a tech note expanding on that, because I did what you've done, although without new fuel hoses and I didn't have a screen in my tank either (thank those POs, and the idea to mark the tank saying it had been removed is always helpful!).

One test I did was bypassing the Racor, so tank>fuel pump>jerry can, which proved the Racor was the culprit and how I found the check valve.  The other one I did AFTER I cleaned the check valve, was tank>Racor>fuel pump>secondary filter WITH THE BLEED SCREW REMOVED.  This proved at least I was getting fuel that far.

I understand your frustration.  I think you're on the right track.  I would continue to concentrate on "sectionalizing" each bit of the system.  You could use your new hoses to bypass the existing hoses completely and see what happens, before you install them all.

I have to go to an appointment now, will think some more about this.  Good luck.

[Gregory M]

Another thing to consider is to check voltage on fuel pump, especially in those higher rpms when your engine stalls, cause, it maybe your pump is deprived of power at that time. C-30 has tank below engine, So it NEEDS fuel pump, not like C-34 above engine.

[hregan]

Stu, thank you for the feedback (and for all your articles and posts - I have learned a lot from your writings).

"Sectionalizing" is on my list. I will take a jerry can of new clean diesel to the boat next week and connect jerry can>fuel pump>secondary filter. This will split my efforts between before/after the fuel pump. My main suspects are the npt fittings on the tank, the racor, and the secondary filter. If it continues to fail after that test I'll zero in on the secondary filter connections, filter seat, and filter bleed screw. If not, then tank fittings and racor.

Gregory - thank you, that had not occurred to me at all. I'm guessing with the sweet running before the clog and subsequent repair it's okay, but it's on my list to check now.

KWKloeber, I hadn't come across the IC30A forum - only the C30 facebook group, where I also posted. I have been overwhelmed with the quality information here on C34.org- particularly on the M25 and boat electrical systems, however I will join the IC30A forum as well and I hope the information is of the same calibre. Of course, I will ensure I properly tug my forelock when communicating with this group. Your post on checking for leaks is superb, and I will try your brake vacuum pump methods next week. Thank you. Oh, and its the 10u on the racor and a napa 3390 on the engine filter. I have been hand-tightening them on fairly forcefully, but both originals (to me) were very hard to get off. The engine filter required wraps of hocky tape to get enough grip with the strap wrench, and the racor required removal and a screwdriver hammered through the filter and another wedged in the base. Good times.

All this is actually (almost) fun. I am learning a tremendous amount about my engine. I could do without the ticking clock of haul-out, but I still have a couple of weeks to spare. If I can get a day with the winds in the right direction, I could sail it out the channel, but I am nervous. If you're bored and want a laugh, google map King Bay, Mactier Ontario. The passage to the west is where I need to get out. The passage to the south does not have a recommended gap to open water, only a winding inside channel south - good for motoring but not sailing.

[KWKloeber]

Oh, and its the 10u on the racor and a napa 3390 on the engine filter.

@hr,

After you get running properly, for you next change, check out on C30 the research I did on filters -- the NAPA 3390 is a WIX filter, among the low-end ones as far as filtering efficiency.  There's better ones available for our engines.

Also, get yourself a motorcycle filter wrench. You need to have it wide open to get on our filters but there is ZERO slip.
I got my cheap @ KMart like 25 yrs ago, but the Lisle 57020 wrench is the size.  Available on Scamazon.com

[scgunner]

It seems like everyone(but me)on this board has a Racor inline fuel filter. Are they OE from Catalina or everyone did replace their original with the Racor? I have a Dahl #61 which has a transparent plastic fuel bowl with the filter element inside.

[Ron Hill]

herg : It sound as though you've checked everything except your fuel lines!!  It sound to me as though you have a restriction (bend? partcial clog?) so the engine used up the fuel available and then dies of fuel starvation.  Then the lines slowly refill when the engine is stopped and the cycle starts all over again.

Go with Stu's idea of going directly from a jerry can to the injection pump.  If that works then do the same by adding in more line and filters.

A few thoughts

[Jim Hardesty]

Herg,
One thing that I didn't see mentioned was a plugged fuel vent, pesky spiders.  The symptoms would show up more after a top-up.  Easy to look at vent then go for a ride with the fuel fill loose or off.  This is something I've seen a couple of times.
Hope this helps,
Jim

[Bobg]

there is a small screen in the electric fuel pump that may be plugged, please keep us informed

[Ron Hill]

herg : As part of your trouble shooting make sure that the electric fuel pump is AFTER the Racor filter.  That way the fuel pump get filtered fuel. 
As Jim mentioned - take an old tooth brush and make sure that the fuel tank vent is clear.  Also make sure that when you open the fuel fill you do not hear a sucking noise (meaning that vent is clogged)!!
You can also try running the engine with the fuel cap off. If it keeps on running for more than 10 minutes that vent and or line is definitely clogged. 

A few thoughts