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Go Back   SailNet Community > On Board > Gear & Maintenance > Strange Power Loss - Weterbeke 27
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Thread: Strange Power Loss - Weterbeke 27 Reply to Thread
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Topic Review (Newest First)
03-24-2008 08:24 PM
kccollbran Since you're experiencing loss in rougher seas, you may also have a loose ground on your fuel pump. If there is a internal float on your pump it may be water (fuel) logged and signaling the pump to shut off. Also, since it's a diesel, it could also be a loose fitting fuel line or a crack in the fuel line, which would cause RPM loss or killing of the engine.

All the suggestions so far have been really good and would be good to check all of them.
03-24-2008 08:18 PM
PBzeer Something else to add in the equation, though this is only my experience. Everytime I've had a filter clog, it's been when I've topped off my tanks with something other than Valtech fuel. Could just be coincidence, but that's been my experience to date.
03-24-2008 08:12 PM
craigtoo Thanks to all for the ideas.

We were under engine power yesterday for about 10 hours straight in calm seas. No problems whatsoever. The engine performed brilliantly.

Two candidates right now for what we believe it is.
1) Crud on the bottom of the tank - clogging the intake.
2) Intermittant blockage of the tank vent. (Crud in the vent line or it may somehow being pinched.)

We're going to trace all the lines in the next few weeks. We'll also have our fuel polished.

Sabreman. Thanks for that data point. Our filters definitely have a dark gray spot on at the intake side of the filter. Looking closely you don't see anything like crud or contaminants.. but if yours are clean, then so should mine.

sadly... I lost the pic I took.

Thanks,
Craig
03-23-2008 08:44 PM
Sabreman IMHO, you filters should be pristine. They should look the same as when you put them in, only wet. I get nervous if I see anything on my filters.

It mat seem obvious, but I recommend adding biocide when fueling.

Let us know how everything turns out.http://www.sailnet.com/forums/images...s/confused.gif
03-23-2008 08:40 PM
Rockter Sabre...

Sometimes it's best to fit an electrical fuel pump... I fitted the Stewart Warner 235A-D... and it will pressurise the fuel stayem to 5 psi. I know there is a fire risk, but having weighed it up, it is better to see fuel leaking out and know about it, than air leaking in and not know until the motor stops.

I suspect that you are picking up crud and slime from the floor of the tank, and your engine mounted lift pump is struggling to feed the motor.

Does your tank have an inspection hatch on there? If it does, get a flashlight and a wee piece of mirror. Drop the mirror to the floor of the tank and shine the light in there. It really should be very clean indeed. if not, then that will be your problem, I suspect.

An electrical charge pump, working well, will mean that the engine lift pump is not needed. Pressuring to 5 psi makes a huge difference. Look carefully at the fuel filter bowl. I hope it's the transparent type. the fuel should be red, and clean.

PM if you wish.

Rockter.
03-23-2008 07:40 PM
craigtoo Let me ask you guys a question.

When you say "fuel pump" you're talking about the main pump that pressurizes the system... NOT the lift pump right?

The lift pump gets the fuel to where it needs to be, but it's the "main" fuel pump which pressurizes the system, and sends the fuel back to the tank. That's my understanding. Right?

Thanks for clarification. 5 years studying mechanical engineering you'd think I'd know a weee bit more.

craig
03-23-2008 07:34 PM
craigtoo
Quote:
Originally Posted by chucklesR View Post
My W 30b does if fact self bleed. I had similar problems to you when I got my boat (and new engine) last year - the problem was the electric fuel pump had a loose connection.
The pump puts out 25 gallons a hour and you are using about 3/4 of a gallon of that, the rest gets recycled thru the tank and filters again. You are in fact polishing your fuel every couple of hours you run your engine - if the pump is running full time as designed. Finding the problem is difficult because as long as it runs every couple minutes you have enough pressure and fuel to run. It's when it goes a while that life sucks.

Check the 12v connection, tighten clean etc..then check the pump. If your really want to get fancy wire a light to the pump side of the connection and put it somewhere you can see it while the engine is running. Then you'll know if it's intermittent. Intermittent problems suck to find.

Eliminate the tank and pickup tube issue by getting a 5 gallon can of diesel and hose then feed the engine directly from there as a test, with the unused fuel going back to the same 5 gallon can (see below).

Troubleshooting possible multiple issues is simpler if you can eliminate one piece at a time.

It might be a air leak - easy way to check for that is to take off the hose that sends unused fuel back to the tank and put it into a bucket, run the engine and see if you have bubbles in that bucket (pre-fill the bucket with some fuel and put the hose under the fuel so you are not making bubbles with flow).
Westy's are good engines, but the electric pumps are somewhat exposed and prone to getting the connections knocked around while doing maintenance. The bad news is a replacement is 158 bucks (I've got two spares, I'll be glad to give you a discount). The good news is - almost any 12v fuel pump from autozone will do the same job for 40 bucks - damn, just killed my own sale.
Fuel pump investigation is definitely on the list... Thanks Chuckles... Great creative ideas ! We're actually all set up right now to run out of known clean fuel supply and bypass the onboard tank all together. But as of now.. no problems... Later on I'll post a pic of what my fuel filter looked like after about 10 hours of operation, and you guys can tell me if that looks normal.. or really clogged.

craig

PS I'm about 5 miles from the bridge now!!!!! ALMOST HOME!
03-23-2008 07:28 PM
craigtoo
Quote:
Originally Posted by danielgoldberg View Post
My guess is that you have a leak somewhere in the fuel line, and it's probably on the suction side which is why you are having trouble finding it. Check all aspects of your primary filter setup and all your hoses and fittings from the tank up through the last pump you have in the line (if you have a mechanical lift pump, that's probably the last in the line, even if you also have an electric pump). For instance, some of the Racor primary filter setups have a plastic screw cap at the top of the assembly. If that cap has a slight crack, you could be sucking air right there. Not enough to bother you with normal operation, but when you get on the thing or it's working harder because of conditions, that might be enough to make it buck. (Take a guess as to how I know this.) Same could be true with a loose connection with a hose clamp, or a pinhole in a fuel line on the suction side (not likely to be on the pressure side because you would be spitting diesel out of the hole and it would be easy to find).

My guess (and obviously that's all it is) is that it's not the fuel. You've refueled a few times, and if it was fuel you'd have the problem regardless of conditions (save for the possibility of churning up junk from the tank, but you'd know if that was the problem when you changed the filters; they'd be clogged with all kinds of nasty stuff).

Another possibility, but I bet this isn't it, is that you might have a screen on the bottom of your pickup tube to the fuel tank. When you're banging around in seas, the junk gets sucked up and clogs the screen. When things settle down the junk falls off the screen and you have better fuel flow. It should be easy to check. Just unsrew your fitting on the tank to which your fuel line is connected and pull it out of the tank (the pick up tube should be connected to the fitting and just lift out). Take a look at the bottom and see if there's a screen. Also, doing this will give you a sense of whether you have algae in the fuel, as the pickup tube itself will have slime on it.

Generally speaking, fuel system problems are easy to find, with one exception, and that's a leak on the suction side. So, if you've tried a bunch of things and can't find it, I'd look hard at every component on the suction side. If you have one, a vacuum gauge ought to tell you if that's your problem too.

Another thought, which hopefully won't be the situation, is that you have bad compression in one of your cylinders. Hard starting and rough running often is a sign of that. That could be caused by a bent rod or a variety of other things. You should hope it's not that, as that will be a more involved (and expensive) process to fix.

All that said, I don't have experience with Westerbeke engines, so it also could be something anomalous to them, in which case ignore all of the above.

Keep us updated. I'm curious to know the conclusion.

awesome ideas... We're leaning right now towards the screen /.crap on the intake too.

This morning before setting out I again, blew into the tank. Following this *very scientific* procedure fuel flowed much quicker from the line into a catch basin. Hmmmmm

Then engine has now been running in calm seas for 6 or so hours without so much as a hiccup. Perfect.

Had compression checked in December... Looks good.

Thanks again for input!

craig
03-23-2008 07:18 PM
craigtoo
Quote:
Originally Posted by Sabreman View Post
Craig,

I strongly suspect that your problem is that there is a screen on the end of the pickup line in the tank. This was (is?) standard for Sabres. When crud breaks loose, it gets sucked against the screen and inhibits fuel flow and results in significantly reduced power (also manifests itself as surging power).

We removed the screen on both our Sabres (28 & 38) and the problem went away. Both engines exhibited symptoms like yours. On the 38, after removal, we sucked so much crud into the Raycor, that it was like jello when I pulled the filter several months later. The filter has been clean ever since. The rationale is that you have 3 filters and it's far easier to replace them than to clean the screen. I'm not sure how your screen is installed - it may be at the end of the pickup in the tank (as in our 28) or it could be at the top of the pickup at the top of the tank (as in our 38). Either way, it's somewhere in the tank, unless the PO removed it (doubtful). Yank the screen and your problem should go away.

You should have 3 filters on your Sabre - a Raycor (#1), a lift pump (#2), and a final (#3). The last 2 should be monted on the engine itself.


Thanks alot for your insight.

I have the Raycor and the final. There have been mods on the lift pump. It has a different version than the one that came stock. NO FILTER.. hmmm

Will investigate further.

Again... thanks so much for sharing.

craig
03-23-2008 01:33 PM
chucklesR My W 30b does if fact self bleed. I had similar problems to you when I got my boat (and new engine) last year - the problem was the electric fuel pump had a loose connection.
The pump puts out 25 gallons a hour and you are using about 3/4 of a gallon of that, the rest gets recycled thru the tank and filters again. You are in fact polishing your fuel every couple of hours you run your engine - if the pump is running full time as designed. Finding the problem is difficult because as long as it runs every couple minutes you have enough pressure and fuel to run. It's when it goes a while that life sucks.

Check the 12v connection, tighten clean etc..then check the pump. If your really want to get fancy wire a light to the pump side of the connection and put it somewhere you can see it while the engine is running. Then you'll know if it's intermittent. Intermittent problems suck to find.

Eliminate the tank and pickup tube issue by getting a 5 gallon can of diesel and hose then feed the engine directly from there as a test, with the unused fuel going back to the same 5 gallon can (see below).

Troubleshooting possible multiple issues is simpler if you can eliminate one piece at a time.

It might be a air leak - easy way to check for that is to take off the hose that sends unused fuel back to the tank and put it into a bucket, run the engine and see if you have bubbles in that bucket (pre-fill the bucket with some fuel and put the hose under the fuel so you are not making bubbles with flow).
Westy's are good engines, but the electric pumps are somewhat exposed and prone to getting the connections knocked around while doing maintenance. The bad news is a replacement is 158 bucks (I've got two spares, I'll be glad to give you a discount). The good news is - almost any 12v fuel pump from autozone will do the same job for 40 bucks - damn, just killed my own sale.
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