M-35 "Third" Fuel Filter Inside Engine Mounted Fuel Pump?

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KevinLenard
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M-35 "Third" Fuel Filter Inside Engine Mounted Fuel Pump?

Guys, I've been through 100 posts in this forum and online and I've examined my engine up close and personal.  I have new filters for the Racor low pressure lift pump and the engine-mounted filter (the one that looks like an oil filter), but despite seeing several mentions of the mysterious 'third' filter that is buried deep within the fuel pump below the injectors, I can find no easy to remove plate or pump part to access this third filter.  Does it actually exist on the original 1991 M-35 (not an "a" or "b" later model)?  If so, where can I find a diagram of where it is and how to access it?  I found no YouTube how-to videos on this specific topic. 

The "Spares Kit" from Catalina Direct for the "Late Sherwood Water Pump Model" does show a red and white cylindrical filter, but before buying this kit and importing it to Canada (nearly doubling the price with shipping and duty taxes) I'd like to be sure the third filter exists on my engine.
Many thanks, Kevin
 

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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Parsons
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I'd love to find it as well.  I bought the replacement parts kit, and found that spare third filter, but I don't know what to do with it.  My engine is the M35BC, and I assumed that it was from the older model engines. I've not spent much time looking at the spare parts diagrams because the filter doesn't look like more than just mesh.

John Parsons
"Water Music" 1999 Catalina 36 Mk II - Hull 1771
Tall Rig, Fin Keel
Bay City, MI, USA

William Miller
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I have a 25xp and the 3rd fuel filter is in the bottom of the electric fuel pump  which I would asume the 35 has as well. The bottom of the pump twists off and you will find the filter there

Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

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LeslieTroyer
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Here is a pic of my spare lift pump showing the twist off cap Kevin is referring to. I've not read about a second filter at the engine.  
 

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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pkeyser
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I'm pretty sure the 3rd filter is the small cylinder adjacent the red reset button on the M35B.

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

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EUREKA
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Hi,

The third filter you are referring to, is the one inside the electrical diesel pump.

Regards

Eladio Vallina

C-36 TR EUREKA II
Hull 1122 (1991)
Home port Barcelona (Spain).

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LeslieTroyer
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I think Paul has it right.  It does look like a filter on the input line just slightly to the left and below from the red button.   That would make four filters on your boat. The Dahl or Racor primary, the filter in the lift pump, the inline filter where fuel enters the engine and the secondary spinn on.

 I would guess you only need the Racor and Secondary.  The other 2 are redundant and probably much bigger micron wise.  

Ther filter on the lift pump is to make sure the check valves maintain pressure if Algie or diesel bugs make it to the pump,  the Racor/Dahl filter should be doing that unless you have big fuel problems.  

I suspect the engine inlet filter is there for instlation that feed directly from the tank.  I don't have that one on my M25. 

Les

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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KevinLenard
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Hm.  Well thanks for the pics and info.  I'll go stare at the old girl some more later today, but my 1991 M-35 doesn't look quite like the M-25xp, nor like the M-35B.  There certainly isn't any easy to twist off bottom portion on the fuel pump, but I will get in there and search some more and will take some photos to post.  K.

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

caprice 1050
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The bottom of the fuel pump is hard tp unscrew, but it will come off. What I did is buy a new fuel pump which works well, then when I had the old pump off I found it easy to take apart. Cleaned off the old fuel filter ,which is only a screen, reassemble the unit tried it out and keep it for a spare. The fuel pump I took off and keep it as a spare is the original and was twenty five years old.

__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050

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KevinLenard
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Well Mike, we should have the same engine, given the age of the boats (but mine has the first of the open tansoms), but when you say "unscrew" do you mean you have a cylindrical "cup" at the bottom of the fuel pump or actual bolts?  To get at the side of mine where there are four bolts I'd really have to dismantle everything on  and around what I believe is the on-engine fuel pump below the injectors.  See photos attached.  There is no cup or inline fuel filter that I can see/find other than the main white filter. 

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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caprice 1050
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Kevin
​My 1990 C-36 has a M-35 (no letters) also.  My fuel pump is nowhere near my motor. It is bolted under the Port side cabin seat in the cabin. There is a fuel line running from the fuel tank, which is mounted under the sink, to the fuel pump then continues back over the side of the fuel tank under the floor to the engine. The fuel pump is mounted vertically with the screen cap on the bottom end of the fuel pump. I find it very easy to unbolt the fuel pump from under the seat. It is difficult to unscrew the screen cap, it requires a great deal of strenght to get the cap off. The cap can be taken off while the fuel pump is bolted to the side of the seat, but I can not physically do it. That is the reason I unbolt it the take the cap off.
 

__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050

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There is a short article on this "third" filter" at the Catalina Direct site ( www.catalinadirect.com/index.cfm/feature/56/the-unknown-filter.cfm ).  Its in the electric fuel pump, which in our MkI is located under the port seat in the main salon.  The bottom opens up with perhaps a 1/8 turn with a  7/8" wrench (never found it needed much strength to do on ours).  "Mainesail" has a nice article on his wonderful site that has pictures showing how to open it and replace the filter, at www.pbase.com/mainecruising/facet_fuel_pump_filter

The replacement filter, pictured below, is available at Catalina Direct (www.catalinadirect.com/index.cfm/product/1634/engine-fuel-pump-filter-.cfm ).  
Mainesail claims that NAPA sells this Facet filter and gasket kit, under their own part numbe 610-1086, for under $10.00, so maybe try an auto-parts store.
 

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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caprice 1050
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Kevin

You should be able to hear the Fuel pump clicking when the ignition switch is turned on. If you need a new fuel pump it can be purchased at NAPA Auto Parts or most auto parts stores. The NAPA part number for the complete fuel pump at NAPA is 6101076. I paid $131.U.S. there in 2015. This same fuel pump is also used for some small airplanes and is available at many airplane parts dealers. I know one of our members bought the same pump from an airplane parts dealers for less than I paid.

__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050

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KevinLenard
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Thanks for all the helpful feedback, gents!  I managed to create an environmental disaster and nearly get divorced on Sunday due to Murphy and his laws.  Some lessons:

  1. YES!  There is a filter in the external "pick-up" fuel pump that delivers fuel to the engine's internal fuel pump through by pulling fuel out of the tank, through the Racor water separator fuel filter, through it's own much larger micron filter (just a safety, I'm guessing as the filter was pristine after 3 years of use without being checked as I did not know it was there) and then delivering it to the fuel filter on the engine where it gets sucked in by the engine's internal fuel pump.  I was very confused by many people referring to the pick-up electrical pump as the only fuel pump -- I thought they were talking about the one inside the engine unless they specifically said "pick-up" -- a newbie misunderstanding.  The filter in the pick-up pump was indeed easy to remove with the twist of a wrench.
  2. ALWAYS carry a spare fan belt, oil and fuel filters, a full container of oil and antifreeze/coolant!  (You all knew that.  I left the dock on Saturday without stopping to work out the fact that I'd thrown out the old, but serviceable, belt and had used the only new oil and fuel filters I had on board to do the oil change.) 
  3. NEVER USE A PUROLATOR OIL FILTER on the M-35a.  It is a bit taller than the others and the alternator 'scimitar' bracket that hold the belt tight comes in contact with it and -- if you make a wrong move -- perforates the filter spraying black oil everywhere and filling the bilge with it.
  4. NEVER USE A STANDARD FAN BELT when what is required is a 40 inch 'toothed' automotive belt.  The more common fan belt will melt and spray fine rubber dust everywhere in the process.  (You all knew that...)
  5. Canadians -- buy a spare pick-up fuel pump when you are in the US.  The one that Catalina Direct sells for $145 USD is $350 CDN at NAPA or $583 CDN via the Westerbeke supplier.

We made it all the way across Lake Ontario on Saturday without incident (4.5 hours) under power.  Coming back on Sunday about 20 minutes out the high heat alarm went off and I found the fan belt had disintegrated.  Luckily I had the serviceable old one in the garbage can on the boat, but while installing it I knicked the new Purolator oil filter and didn't notice.  We got exactly to the mid-point of the lake and the tachometer dropped to 8,000 while the engine continued sounding normal, the the RPM's came back up, so I shut the engine off to see what was causing the anomaly.  Black oil had gushed everywhere and no replacement filter to fix things. 

We sailed home in a brisk wind that had me picturing the thick, black sludge in the bilge sloshing around and coating the entire underside of the floorboards. Of course the wind died after several hours.  We arrived in the dark at 11 pm with no engine so we had to anchor outside of our club's harbour.  In the morning I lashed the swim ladder on top of the dinghy's bow and pushed the old girl into the harbour and our slip. 

Surprisingly after a good night's sleep out at anchor, the Admiral was in fine spirits and left me with the admonition that she better return to a fresh smelling, 100% clean vessel on Friday.  It took me about 6 hours to suck the bilge clean with the vacuum pump, lift the floorboards and clean the oil up.  I am now in the process of buying back-ups of everything I can conceive of.  Oops. 

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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