Enigine RPM's up & down

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Feb 26, 2004
23,348
Catalina 34 224 Maple Bay, BC, Canada
Jimmy, very good point, that's why the ideas

in reply #11 were developed.
 

AXEL

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Mar 12, 2008
359
Catalina C30 MKIII WEST ISLIP, NY
REPLY

Good replies thanks all for your suggestions. To clarify, the screen at the tank pickup was removed a long time ago so that’s not an issue. I am suspecting that it might be something simple like a clog in the fuel line (or tank fittings) and I plan to replace that section of fuel line this weekend. I'm also going to follow-up on Jimmy's suggestion (reply #19) although I have never noticed a screen in the fuel pump before but it's worth a look. Also as a result of reading a separate post in the forum this morning on the subject of the tank vent I am going to give that a quick check, something as simple as a spider web in the tank vent could cause this problem too.
 

RAD

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Jun 3, 2004
2,330
Catalina 30 Bay Shore, N.Y.
I was told by a diesel machanic

About a filter screen in my lift pump on my Westerbeke and to keep an eye on it cause most people don't know about it then when I bought the back up Walbro electric fuel pump it also had a 70 micron filter screen in it so it sounds like it might be the last place you look
 
Feb 26, 2004
23,348
Catalina 34 224 Maple Bay, BC, Canada
RAD, yes that's right, except it becomes

a NON-ISSUE if you "correct" the piping and run it from the fuel tank to the primary filter and THEN to the fuel lift pump.
 

AXEL

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Mar 12, 2008
359
Catalina C30 MKIII WEST ISLIP, NY
correct piping

My boat is piped as follows; Fuel tank - primary fuel filter/water seperator - fuel filter/fuel pump - small fuel filter on engine - to injectors. Most of the time when I change fuel filters the only filter that looks used the the primary. the other 2 always look like new. I'm going to do a search and look for a breakout of the fuel pump and try and find that filter screen.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Have you checked your tank vent

Have you checked the tank vent. You have probably already done this, but didn't see it mentioned. Also I don't see a filter screen on the intake side of the pump, but item # 8 sure looks like a filter to me. On my Yanmars, that is a seperate item, but it is there between the lift pump and the injector pump. It is a 2 micron and very small. Don't want to be repetitive here, but still think it is something pretty simple.
 

AXEL

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Mar 12, 2008
359
Catalina C30 MKIII WEST ISLIP, NY
Thanks but

Thanks NNE, I did mention in a previous post that I just noticed a discussion in another post today about tanks vents and it will be on my list of things to look at this weekend. Yes, item #8 is a filter and it was just changed along with all the other filters.
 
Feb 26, 2004
23,348
Catalina 34 224 Maple Bay, BC, Canada
AXEL, it's right above #7 on your sketch

it lays on the bottom of the pump just above the bottom housing. There's a nut on the bottom of the part #7 that you use to get it off. If you look closely at parts #2 (the body) and #7 (the bottom), you'll see the tips on #2 that hold the slits in #7. Or you can read the link I posted in Reply #11 and see a picture of that very pump. While your plumbing seems to be right, there's no telling when the correction was made and the pump's filter could well be clogged from previous use. Good luck this weekend, I think you have enough information from this thread to be dangerous - and repairable. :)
 
Oct 17, 2005
119
Catalina 30 Edmonton
Tank venting?

Check the fuel tank vent and make sure it is clear. You should not have a totally sealed unit. The length of ttime you ran down to yowards your slip before you had trouble makes this a possibility. Let us know what you find Good luck Ken
 

AXEL

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Mar 12, 2008
359
Catalina C30 MKIII WEST ISLIP, NY
Problem solved!

I got down to the boat over the weekend. The weather wasn't that great this weekend here on Long Island. My plan this weekend was to step the mast (I have a taberknackle rig for my C30) and to put on the sails and canvas. When I got to the engine the first thing I did was remove the fuel line from the tank and the main fuel filter. I blew the line out into a container. A small amount of fuel came out without any restriction and the fuel looked clean. I was hoping for the opposite. The next thing I did was to reattach the fuel line at the fuel tank. When I blew this time my cheeks billowed up like I was blowing a trumpet. I was thinking it should not be this hard to blow bubbles in diesel. My fuel tank has a small 90 degree fitting with a shut off valve going into the tank. I inserted a pipe cleaner into it and felt restriction. I worked the pipe cleaner in & out a couple of times until the restriction was cleared and reattached the fuel line. When I blew through this time there was no restriction. Although I did not get a chance to take the boat out this weekend I feel 99.95% confident that was the problem. Thanks to all who replied to my post, I appreciate all your feedback
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Way to go

Way to go. Never give up. And always look for the un obvious and simple first.
 
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