M35B, Bleeding the engine

[Stewartn]

Confused. Universal Manual says under normal circumstances bleeing is unessary. There is no bleed screw on the lift pump. Other local owners claim that just energizing the liift pump and then cranking the engine will atomatically bleed it. Any 1st hand info on changing the filters and starting the M35B engine is greatly appreciated.

Thx.

[Jim Hardesty]

Just a caution on cranking the engine too long.  The manual warns that after 30 seconds the muffler will fill and may allow water to enter the engine if not drained.

[Steve Sayian]

Stewart,

The bleed vent is above the injector pump.  The M35's fuel pump doesn't engage when you turn the key on like the M25(X). 
I have a Racor fuel/water seperator on the Stbd side under the aft bunk area just behind the stuffing box.  There is a thumb dial on the top of the filter assembly that you unscrew and it can be lifted up and down to bleed fuel through the Racor and then through the final filter on the engine.  You have to open the bleed valve on the engine first (and place a coffe can or other suitable container to catch the fuel).  It's a bit cumbersom moving back and forth so an additional pair of hands to close the bleed valve might help.  Otherwise, it's pretty easy.

Hope this helps.

Steve

[Jim Hardesty]

Sounds to me like a switch to run the fuel pump with the engine off would be a good idea.  Can anyone think of a downside?
A sign of spring.....Lake Erie has more water than ice.

[Stu Jackson]

Gentlemen with M35 Engines

I believe it is critical that you read this very loooong thread:  http://c34.org/bbs/index.php/topic,3347.45.html

Starting with Replies #52 & #59 on page 4, and the conclusions expressed on page 5, Reply #63, it discusses the operation of the M35 engines and the fuel pumps.

The M35 engines have an "improved" wiring scheme that turns the fuel pump off unless the spring switch is on glow plugs or the oil pressure sensor is satisfied.

PLEASE read the thread and especially the recommended replies for a detailed discussion.

The unintended consequences of this "new, improved" (and, I believe, silly) wiring change is exactly what prompted Stewart's original question.

Your boat and your choice of how to handle the issue, based on my suggestions and Ron's input, too.

[Hawk]

I just changed my primary filter (not the Racor) on the weekend on my 1990 M35. I used the fuel pump by turning it on with the key to bleed the system..no problems.
Here is a useful thread:

http://c34.org/bbs/index.php/topic,2884.0.html

Do a search from the main message board on fuel filters...lots there.
Hawk

[Stu Jackson]

Hawk,

Thanks for doing the search and providing the link.

One of the things we keep repeating is that you identify the specifics of your boat in your avatar or signatures, or at least in your questions and posts.

Bleeding techniques are DIFFERENT for different engines.

That was the purpose of that loooong thread I mentioned above.  The M25 series and M35 engines are DIFFERENT.  The wiring is DIFFERENT for the fuel pump operation.

What engine you have makes a DIFFERENCE.

Get the drift?

Try this: http://c34.org/bbs/index.php/topic,1506.0.html  See my avatar and my signature for an example.

[ed webb]

I changed my filter last year. took about 20 to 30 minutes of cranking to get all of the air out. My friend owns an excavation copmay that runs all diesel. He bled the lines while I turned the key. He suggested that the next time I fill the filter with fuel first. This cut way down on the amount of air that get into the system.

[Stu Jackson]

Yes, Ed, that's good idea, because introducing more air just isn't a super idea, although the fuel pump does a good job of it.  In any event, we read a lot of the old material and one suggestion from Ron Hill is to use injector cleaner to fill the new filter.  I find it's kinda hard getting fresh diesel fuel to fill it, unless you remove the fuel filter vent and open the fuel valve from the tank.  Then you have to replace the vent screw which is hard to get to.  We just pour the injector cleaner from its little plastic bottle and we're done.

[Hawk]

Just as clarification, its the Racor secondary filter that you might consider filling. The thread I posted above, and my experience, is too NOT introduce any fuel into the primary engine mounted fuel filter. Why take the chance of contaminating at that stage. I just clicked over the fuel pump for 20 or 30 seconds and done.
Hawk

[Stu Jackson]

Reading the information available on on this website related to primary and secondary filters, and "BLEEDING" (which is "the" word to use for searching on this topic in addition to "fuel filters") it's important to recognize the definitions of each filter.  The primary, or first, filter, is the Racor, the secondary is the one on the engine.  

The reason for this is that the Racor (under the head sink on the older boats) comes FIRST.

The secondary filter bleeding usually, but not always, requires that the bleed screw on the top of the secondary (engine mounted) filter bracket/housing needs to be unscrewed most of the way or completely removed to remove the air from that end of the system.  That's why some folks have installed fuel pump shutoff switches in their engine compartments so they can bleed their engines without having to need either two people (one in the cockpit at the key switch for M25 series engines and one at the engine) or very quick fingers to reinstall the secondary fuel filter screw.  I believe there is a wiki on this.

Even "self-bleeding" M35 engines could well require bleeding if the secondary filter is replaced - I just don't know because I don't have an M35 engine.

I agree that filling the secondary filter, with anything, is almost impossible and shouldn't even been considered, because it requires a three handed four armed left-handed monkey to remove and replace that filter on the lower starboard side of the engine.  

[Jack Hutteball]

Well.... not really.  On my 2001 with the M35 engine, there is a door in the bulkhead near the secondary filter on the starboard side of the engine.  I have to get my head friendly with the cabin sole, but it is easy to do.  I carefully fill the filter to the top, screw it on, and she is ready to go.  The primary filter under the aft cabin bunk, I let fill by gravity after changing the element.  I don't screw it on tight until it fills and just starts seeping over the edge and a quick turn tight, wipe down the outside and I am ready to go.  Always starts in about 10 seconds and never had to bleed anything.  Change the primary every 50 hours or so and the secondary about every 3rd time.  The problem I have is taking the old filters (both) off without spilling fuel all over the place.   Maybe I am just lucky about the bleeding, but I asked a rep at a boat show about bleeding as we looked at an M35 on display, his response was that the M35 is self bleeding and does not need it.

[Hawk]

Thanks Stu. The thread I attached above at reply #13 refers to the Racor as secondary which struck me as odd but I went with it.

We certainly need to be consistent.
Jack,
I will try filling the "secondary" filter next time as you did. I also have the access door in the strbd bulkhead. But can you expand on "M35 is self-bleeding". I take it this means there may be occasions when we don't need to use the ignition switch to run the fuel pump while opening the bleed screw(as worked for me last week)..or............ ?

Thanks, Hawk

[Jack Hutteball]

Hawk,  with both filters full, I just turn the key to the glow plug position so the fuel pump is ticking, count ten seconds, and hit the start button.  The engine always fires right up.  I never just run the fuel pump a long time without starting the engine.  This is always the way I have done it and the engine has never missed a beat.  After replacing the filters I also run the engine at the dock for 5-10 minutes with the transmission in gear to put the engine under load while I check for leaks etc. I usually change my oil filter at the same time so this gives me assurance everything is operating Ok with no leaks.  Clean engine, clean bilge, admiral happy.

[Ron Hill]

Guys : Just remember that it only make sense to fill all of your filters to the top with fuel.  I've mentioned this MANY times, so you introduce the least amount of air into the fuel lines/system
You all have a bleed bolt on the top of the engine fuel filter - use it.
 
If you are worrying about cranking the engine over and filling the muffler (as your caution placard says); knowingly shut off the raw water thru hull and crank to you hearts content (don't burn up the starter!!)!  When the engine starts you have plenty of time to go below and turn on the thru hull for the raw water.  Up to one minute of running without raw water is not going to fry the muffler or destroy a normal impeller.