Pressurizing fuel, hard starting, dirty fuel/tank, bleeding air, new fuel pump

[Michael]

This posting relates to hard starting of a Universal M-35B engine on a 1997 Mk II (hull #1352) and several of the possible causes that have been identified at this site including air in the fuel lines, dirty diesel fuel, dirty diesel tank, malfunctioning fuel pump, and bad or misplaced electrical connections to the fuel pump.  One solution to this problem that is identified here - pressurizing the fuel in the tank - is, I think, a new approach that seems to work on our boat, although quite why is a bit of a mystery.

For the sleuths who might have some advice, here is the problem and what has been done about it so far.

After extensive engine work (new hoses, new propeller shaft, new heat exchanger,...) on this boat after purchasing her in March, the engine started fine on a fuel tank something over half full.  We - Hali is a joint enterprise among four ownership groups - motored for about three hours then crossed Georgia Strait in a lumpy sea (30+ knots of wind) on her delivery voyage to Vancouver.  No doubt the fuel tank (which later inspection leads us to believe had not been cleaned since the factory although the fuel had just been polished) got a good shaking up.  Over the next couple of weeks, we motored occasionally, intentionally drawing the fuel down in the tank without refilling the tank as we wanted to remove the fuel tank, inspect it for gunk, and, if necessary, clean it.

During this time, as the fuel level dropped, a "hard starting" problem developed.  It seemed (to me anyway) reasonable to conclude on the basis of other postings that the fuel was dirty (from the crossing stirring up the old tank) or the fuel pump was failing, or both.  Later, I realized on the basis of postings at this site, that when the fuel level is more than about half-tank, no fuel pump is necessary, so a defectively operating fuel pump might not be noticed (I conclude) until the fuel level is below the magic self-siphoning level, because until then the fuel then feeds the engine by gravity flow as from a day tank.

Influenced by Ron Hill's posting on the joys, ease, and necessity of cleaning the fuel tank, we embarked upon that venture, thinking a clean fuel tank might solve the hard starting problem. (We have concluded that you are an alien, Ron, who lures unsuspecting C34 owners like us on to great feats in the mistaken belief that they can accomplish them as easily as you do.)  Sure enough, to the extent we could see down into the tank once it was removed, the bottom of the tank was covered with gunk (asphaltine?).  Removing the tank as Ron recommended was to this extent very useful. Although four gallons of acetone and two days later, the tank was a lot cleaner and the acetone coming out was clear instead of dark brown as it had been at the beginning, we concluded that the only real way to clean the tank would be to cut proper clean outs in it.  You would need two cleanouts we figure, one each side of the baffle, in order to allow mechanical cleaning.  I have seen a posting on this site since where a poster mentioned cleaning inside the tank using a Scotch pad on a spring poked down through one of the small fuel supply holes, but by then we had the tank back in the boat and I am skeptical that the bottom gunk can really be cleaned off without a wire brush and considerable mechanical force.

After installing the cleaner fuel tank and filling with about 5 gallons of new diesel, we bled the fuel lines and tried to start the engine.  The hard starting problem had not been solved.

We then changed the engine-mounted electric fuel pump.  (We had done inadequate investigation of the OEM pump's electrical connection and power supply but did ascertain that when the house battery was switched on and the key was on but not to the glow plugs the pump received 12 volts.)

We used the NAPA Posi-Flow "universal electronic fuel pump" (NAPA part number 610-1051) that has been recommended at this site and found to our delight that the bolt holes on the pump lined up with the holes on the engine bracket where the old pump had been.  Not quite so ideal was that the negative lead on the new pump was not long enough to reach easily to the most convenient bolt on the engine frame.  (We Marr connected, soldered, and taped another wire to the lead to get the length we needed.) 

The new lift pump seemed to work.  It whirrs more quietly than the old OEM pump but is still audible from nearby.  But the engine would not start.

We then filled the fuel tank to nearly full from jerricans ("hose to tank from jerrican" and "pressurize the jerrican by blowing through another hose" - as recommended at this site), but the engine would still not start.

We then "pressurized" the fuel tank itself by stopping the fuel vent while blowing into the fuel fill through a short piece of hose.  (The fuel vent is located, at least on Hali, on the port side of the walk-through transom.  Two fingers holding a plastic bag work fine to stop it up.  Use a plastic bag also to stop the air from escaping from the fill pipe as you blow down there.  For those of you who don't like the taste of diesel, a short piece of hose not put into the diesel fuel is recommended as a blow pipe.  It seems that otherwise, when you stop blowing, the air pressure forces the diesel back up your blow hose.)

Just to make sure our previous fuel line bleeding efforts were reinforced, during this pressurizing effort we also opened then closed the knurled bleed valve handle on the fuel line just before the fuel injection pump.

After the fuel tank was pressurized, the engine started immediately.  It seems pretty clear that pressurizing the fuel tank caused fuel to reach the engine and that that had not been happening before.  After starting, the engine ran fine and started fine on the same day.  We don't yet know whether the good result will carry over to another day.  We like having a sail boat but draw the line at huffing and puffing at its fuel tank every time we want to go sailing.

Does anyone have an explanation for what happened -- why pressurizing the fuel tank worked?

Do you think we will we have to pressurize the tank next time in order to start the engine or will the engine now run without it?

Regards.



 

[Ken Krawford]

Michael,

Your very detailed posting did not mention changing of the primary and secondary fuel filters.  I'm assuming that they were replaced, but in the event that they were not, is it possible that they are partially clogged and the pressurization was enough to overcome a partial obstruction?

[Stu Jackson]

Piggybacking on Ken's note, one thing not mentioned is fuel LINE replacement.  Having the tank out would be a good time to do that as well. Could it be that there was something in the lines that got knocked out?

That's a great writeup and description, thank you for the time you took to prepare and present it.

[Michael]

Thank you for the immediate feedback.

We had the fuel filters (primary and secondary) changed just before the crossing, so they could have become clogged in the crossing, but we changed them again after cleaning the fuel tank.

The fuel lines are, I think, mostly old -- or at least not new.  We did flush some particulate matter out of the fuel line upstream of the primary (Racor) filter just after we re-installed the cleaned fuel tank.  Now that I think about it, the engine did start once just after that but as we were also bleeding the lines at the time and doing other things the significance of cleaning the line out a bit did not particularly strike me.

Stu, are you thinking perhaps that when we pressurized the fuel tank it created enough pressure to overcome something in the fuel line?  You have given me something to think about there.  I wish now that we had replaced at least that primary fuel line when the fuel tank was out.

Cheers.

[Ron Hill]

Michael : Sorry if I led you astray!!  My article said that I couldn't find anyone that would clean my tank so I devised my own method.  BTW, I don't know what your outside temp was the day that you used acetone, but warmer temperatures always enhance chemical reactions.  I did mine in July about 90F.

If you pressurized the tank to get the engine started it means that the fuel is not flowing freely!  Did you make sure that the pickup tube was clear when you had the tank out?  You should (with a full tank) be able to loosen up the Racor filter and have fuel syphon.  Did you remove the fuel line from the injector pump, turn on the key switch(activating the electric lift pump) and have fuel come out of the line?
Think you need to start at the fuel tank and find the restriction that is causing the lack of fuel at the injector pump!!  I doubt on your age boat if the fuel lins are bad - crimpt maybe or bent !!
By all means make sure that you have clean filters!   

[Michael]

Ron, thanks for your post.  We would probably never have dared to remove the fuel tank if we hadn't known someone else had done it successfully, so your write-up was a good motivation even if it did take two of us about 5x as long as it took you.

Our two days of washing the inside of the tank with acetone were warmish (say 70 degrees F), not hot.  As we got a lot of gunk out we are pleased with the job even if the result is not as good as hoped.  We would have liked to see shiny aluminum.  In the end, I would conclude that acetone is somewhat effective but if I were doing the job again I would plan on cutting two quite large cleanouts (probably in the top of the tank so there is not quite the leakage possibility as there would be from side tank cleanouts) through which to reach to scour the inside with a wire wheel on a drill bit.

Ron, we did make sure the pickup tube was clean when we cleaned the tank.  And that pickup tube, apparently unlike those of some owners/posters, did not have a filter or screen in it.

Since writing my first post in this thread, the hard starting problem has persisted on the one re-start attempt, albeit in a somewhat attenuated form.  The engine started on the 5th cranking last night, with glow plugs energized before the first and fifth cranking, but with no re-pressurizing of the fuel tank.

I think you are right, Ron, that I need to start thinking about the problem at the tank and work from there right to the engine.  As the gremlin who has seized Hali seems to be a precocious fellow, the process of thinking through and testing the possibilities for mischief may result in a "things to check" list that, with input from others, could be made comprehensive.  In any event, I think it will help to make notes each step of the way, because it is easy to do several things and forget their sequence.  For example, you asked, Ron, whether we removed the fuel line from the injector pump, turned on the key switch (activating the electric lift pump), and had fuel come out of the line.  The answer is that we did that but before we changed the electric fuel pump, not, I think, afterward. Also, I said rather glibly above that the electric fuel pump had worked when the key was in the on (not glow plug) position...but in the absence of a note to that effect I am now beginning to wonder whether it was so.  I am a bit mystified about when and why the fuel pump is activated.

As ever, thanks for great help.  I'll try to report the outcome.

[Stu Jackson]

Another why-didn't-I-think-of-it:  U wrote: "The engine started on the 5th cranking last night, with glow plugs energized before the first and fifth cranking, but with no re-pressurizing of the fuel tank."

To clarify, there is no need to hold the glow plugs in when the start button is pushed.  If done so, hard starting does occur.

Press glow plug.  Release glow plug (you can even wait 5 to 15 seconds).  Hit start button.

Also, do you have the throttle advanced a bit, say to about 1100 rpm when it starts?

[Michael]

Stu, thanks for the follow up.  I am trying to read as much of this site as I can and so, yes, I had come across advice previously about only energizing the glow plugs for a short time (5-10 seconds seems to be something of a consensus, at least in my memory) and then, with the glow plugs no longer energized, hit the starter -- and that is what we have been doing.  Although I am going to follow Ron's advice and work methodically through the possibilities for fuel starvation beginning at the fuel tank and working to the fuel line connection just before the injector pump, the most likely candidates (and there may be more than one gremlin of course) seem to me to be these:
- plugged fuel tank vent line
- undiscovered muck from the fuel tank re-plugging the pickup tube
-  pinched/plugged fuel line from the tank to the primary filter
- loose clamps/fittings allowing air into the fuel line
- intermittent electrical failure in the fuel pump electrical circuit
- inadequately bled fuel line

With respect to the possibility of an intermittent electrical failure in the fuel pump electrical circuit, there were some odd, weak-and-wierd sounding low oil pressure warning sounds - I suppose that is what that regular beeping-before-starting sound is - when I started the engine last night.  I need to get out the wiring diagram for the fuel pump electrical circuit because it seems that we have a double positive wire as far as the fuel pump, so I suppose the fuel pump and another circuit (low oil pressure?) are wired serially.

The foregoing is more of an aide memoire than a request for help, as I have some homework to do.

Cheers and thanks again.

[Stu Jackson]

Report from Ron by email to me:

Stu : I'm in a bad area and keep getting disconnected!! 
Will you make a post for Michael that I know of instances where the factory miswired the M35A engines.  They put the electric fuel pump on the third (post with glow plugs) spring loaded rather than the second (ON) pole of the key switch.  This warrants checking!  Could have easily happened to his boat!!
Thanks Ron

[Stu Jackson]

Good that you are being methodical.  Step-by-step is the only way to go.

If you have a glow plug solenoid, then the short 5 to 10 seconds is still not quite enough.  Without the solenoid, 30 seconds was required for the long wiring run up and back from the panel.  WITH a solenoid, 12-15 seconds is about right.  Try it with a bit longer glow plug hold-in.  I use 12-16 seconds when it's cold here (brrr-all of 50 degrees is cold for us!).  If the plugs don't heat up the chambers, you're gonna get a rough start all the time.

If your fuel tank is full, the fuel pump connect should be a non-issue except for finding out why it's not working properly.  See Ron's input above by his email.

Check the ground wiring for EVERYTHING.  Many folks forget that side of the equation.  Check the push buttons, too.

OK, OK, we'll leave you alone while you do your homework.   

All the best, keep in touch and do good work...

[Michael]

Thanks, Stu and Ron.

At one point, Ron, I had seen your old posting about the fuel pump sometimes being miswired to the glow plug circuit instead of being wired to the key-on circuit.  Whether that is so for Hali's M-35B is, as a result of your reminder, now back on my "things-to-check-better" list.  For the nonce, however, I take some solace in the thought that the fuel pump may be irrelevant given Hali's full fuel tank and its "day-tank/gravity feed" effect previously discussed.

Stu, I appreciate the advice to energize the glow plugs for 12-16 seconds (i.e., somewhat longer than we have been doing recently) ...and collaterally to check whether the glow plugs on Hali are on a solenoid circuit or wired directly through the key.  Early on in addressing the hard starting problem, we had gone to energizing the glow plugs for as much as 30 seconds or so...before reading somewhere that doing so could damage them.  We then backed way off, to the 5 seconds or so that we have been using recently, partly because I read one of the posters here who said that he had never needed to use the glow plugs for more than five seconds.  I suppose he was in a warm area, but the weather in Vancouver is generally pretty mild, too, so query how much need for the glow plugs there is.  Also at one point in the hard starting exercise, I tried warming up the cylinders using a heat gun.  Although my recollection is that I got the engine started on that occasion, I can't say (or remember) that using the heat gun really helped much.  However, your advice to try the glow plugs for longer puts in mind that when the engine did last start, on a fifth cranking, I think I did energize the glow plugs for slightly longer than before the occasions (cranking #1-4) when the engine did not start.  So perhaps there is something there.

Unfortunately, the gremlin just keeps popping up in so many fetching disguises that it is tough to stay on a methodical approach and not go chasing after his latest incarnation.

Will report the outcome...after that homework.

[Ron Hill]

Michael : If your engine will start after it's been run been warm, you might have a glow plug problem.  Can't tell you what a worn glow plug looks like?  Pull one of your glow plugs and take it to a Kubota dealer to get replacements - the Universal (SAME) part is 3to4 times as much $$!  Not too sure if the M35 has the same glow plug as the M25XP?? 
Good luck   

[John Sheehan]

A couple of thoughts on the hard starting.

Be sure the fuel line connections to the fuel tank are perfectly sealed so no air could leak into the system and break the siphon action on the suction side of the fuel pump.

Also on the M-35B wiring at least, the fuel pump is only on when the glow plug is energized or when the key is in the running position with oil pressure.  If there is no oil pressure (or if the wire on the pressure sender is not connected) the fuel pump will not function.  You can jumper 12 volts to the fuel pump to see if it works at all.  I also use a jumper to run the fuel pump to fill the filters after changing them out.


More on Hali's issues:  http://c34.org/bbs/index.php/topic,3347.0.html

Stu

John

[tonywright]

When I acquired my 2003 MKII, I had an engine surveyor check a number of things on the engine. The first was hard starting. He quickly found that the glow plug solenoid needing replacing. After that, she starts instantly every time after approx 10 secs of glow.  Worth checking on yours?

After replacing the batteries with Rolls/Surette 4D's, made sure that the connections were super clean and super tight on the battery terminals. (Used Deoxit to clean, and wrenches to tighten). Did not tighten enough at first, and starting was poor...(yep, always the same thing, but had so many connections on one post and never needed them that tight on my last boat).

Curious on one thing: I wonder why the Universal manual requires glow to be applied after start until oil pressure is up, and yet the advice on this board is to stop glowing before starting? Is Universal really that bad at writing manuals?

Tony

[John Sheehan]

Tony,

Possibly since the fuel pump does not operate until the oil pressure comes up, they want you to hold the glow plug on to keep the pump running while starting.

I have been following the ideas on this board and not running the glow plug when I hit the start button.  Many times in the summer I don't even use the glow plug and the engine fires right up.

John