Diesel dying after running at 2k RPM few hours.

[model 10]

Originally Posted by phorvati

Maybe i get the electric one instead.

I just tossed my mechanical pump in the trash. I bought a spare electric that I will probably never need. Much faster pump to change if you did need to and it will never put fuel into the engine. If you can start the engine you would have enough juice to run the pump. I can run an electric pump forever during the day and the batteries could handle the night no problem.

[bruceinOz]

I've been going through the same problem for the last few months.
The engine died only once, but other times would run strongly and then suddenly struggle. Revs would drop, some smoke would appear, hardly any power, of course same time there'd be no wind and a coal ship coming up the harbour (of course).
Then mysteriously it seemed to fix itself, bizarre.
Changed, replaced all hoses and filters, bleed it, etc and it's all good.....till...
Last time it happened I realised I had to get into the fuel tank. Completely glassed in, so we had to cut inspection holes and drain and scrub the tank. Disgusting job. Some floating crud in there, maybe enough to block the pickup.
Installed a new pickup and a new separate breather line, no longer teed into the return line, and now let's hope I've fixed it.
By the way, I also put in a small deck filler opening into the tank so I can use a dipstick to actually know how much fuel I have. It'll be a lot, the bloody tank is 130 litres and it's only a little 32' yacht! A range of over 400nm is good I guess, but I only motor a few hundred metres from my pen. 😀
Good luck


Sent from my iPhone using Cruisers Sailing Forum

[svlamorocha]

R20s is a 2-micron filter. That is a bad idea.

Sent from my SM-G9287 using Cruisers Sailing Forum mobile app

[RaymondR]

I had this sort of problem once and found I had put both fibre washers on the same side when I reinstalled the inlet banjo fitting onto the lift pump.

[BigNickMontana]

Make sure your tank vents aren't clogged, this can have the same effect.

[phorvati]

Originally Posted by svlamorocha

R20s is a 2-micron filter. That is a bad idea.

I was just going over my logic on that. I double checked, wix 33166 is my secondary (10 micron), and R20S is 2 micron, my primary.
that doesn't make sense. I wasn't very diligent about the micron ratings when i installed the engine. Not that this is causing the problem, but it can't help.
So do i go 30 micron (primary) 10 micron (secondary)? Leave the wix which was changed last spring.

I'll check the compression nuts on all inlet copper line. i know i did not replace all of them back in 2012. Only the ones that looked bad, but i never really tested for vacuum or air leaks. I have spare nuts and spare copper fuel line.

And with that wix secondary filter, there is always something mysterious on how its installed. That top gasket can easily move and not seat properly against the top flange, and I would get a leak during priming. I wonder if air is coming in that way. I don't have good access to feel back there that its absolutely leak free. If fuel is leaking there during priming, I would think that air could come in at high RPMs.

Form reading other posts, CAV DPA IPs (distributor type) are very susceptible to air at inlet. Does anyone know what the inlet pressure at Injection pump should be at idle or at cruising RPMs? I would think that Vacuum there would be a problem.

[phorvati]

I think this is my problem. TAD inc, has a write-up on it. I place the gaskets but never really followed these, and if engine starts after priming, I think I am good to go.

[RaymondR]

Originally Posted by phorvati

I think this is my problem. TAD inc, has a write-up on it. I place the gaskets but never really followed these, and if engine starts after priming, I think I am good to go.

I have had so many problems with this type of filter and it's multitude of gaskets and O rings that I have mounted the filter on a piece of plywood which fastens to a bulkhead with two wing nuts. I can readily unfasten the filter and turn it upside down to replace the gaskets, element and base and have had a lot less problems with leaks since doing so.

[svlamorocha]

Originally Posted by phorvati

I was just going over my logic on that. I double checked, wix 33166 is my secondary (10 micron), and R20S is 2 micron, my primary.
that doesn't make sense. I wasn't very diligent about the micron ratings when i installed the engine. Not that this is causing the problem, but it can't help.
So do i go 30 micron (primary) 10 micron (secondary)? .

30 should be ok for primary that works in suction
10 is reasonable for secondary unless engine manufacturer says something unusual.
All that said, by going from 2 to 30 you are reducing suction downstream of primary. This will reduce likelihood of vacuum leaks. Even if the leaks disappear I would find and correct the leak points anyway to be safe.


Sent from my SM-G9287 using Cruisers Sailing Forum mobile app

[phorvati]

Originally Posted by shakey doug

Remove lift pump lid and clean filter screen.

I could not find this screen. Where is it? Rebuild kit for the lift pump did come with a screen. I took the lift pump top housing, and replaced the diaphragm as that looked pretty stiff. I tried taking the valves off unfortunately the new valve was not an easy fit into its slot. I damaged one as i was putting it in. So i left the originals. They did not look bad.

I put a 30 micron primary and a new 10 micron secondary filter.
I did find a lose 3/8" flare to 1/4" barb fitting at the input of lift pump. It was just hand tight. So that could have contributed to air coming in.

I have 5/16" ID line to primary filter housing , then 1/4" line to lift pump, then its the copper tubing with compression fittings. i believe those are 3/16". My hope is that combination of fuel line sizes does not create a problem.

I bled the engine but did not start it yet.

[Cruisingscotts]

A couple things, you should not be running your return fuel into your tank vent, higher revs more return fuel more chance for air locking the tank. If your tank has a down pipe it may have a leak in it up higher on the tank or a loose fitting. The easiest way to check your fuel supply is to instal a cheep vacuum gauge after your racor filter, pretty straight fwd. if you are pulling a vacuum you have a restriction somewhere down stream. Also some racor housings have a ball check on the inlet that can gets stuck.

[svlamorocha]

Originally Posted by Cruisingscotts

Also some racor housings have a ball check on the inlet that can gets stuck.

I hate those check valves that are not "advertised" by Racor.


Sent from my SM-G9287 using Cruisers Sailing Forum mobile app

[phorvati]

Thanks. I get the high rpms and return line. Now that's looking like a very likely scenario. I guess another hole in the tanks is imminent. I had the tube out last year. It was in good shape. I started the engine today. Didn't go for a ride, but I ran it for few hours to make water and saw no fuel leaks.

[Cruisingscotts]

Originally Posted by phorvati

Thanks. I get the high rpms and return line. Now that's looking like a very likely scenario. I guess another hole in the tanks is imminent. I had the tube out last year. It was in good shape. I started the engine today. Didn't go for a ride, but I ran it for few hours to make water and saw no fuel leaks.

Before you go to far I would do the vacuum check, you can make a simple manometer with a piece of clear tube/ hose and a T after the racor. As long as the tube is well above the tank, bend a couple feet in a tight S shape and tape that way wiht the open end up. Put a small amount of fuel in the open end so you have several inches in the bottom bend. Run the engine and watch the levels of fuel, should be relatively static.

[Lojanica]

I would get a new 5 gallon jug and a short stretch of fuel line with an inline 10 or 20 micron filter and make a temporary day tank. Make sure all the fittings are new and tight. You will quickly figure out if it is a supply or leak in your regular cicuit. Day tanks are nice just for that reason. No crud, easy to clean and refill with fresh fuel. Can be raised to give positive fuel pressure in the case of a poorly performing lift pump, etc. Also cheap way to figure things out quickly. You may decide if it helps you out to make a more permanent day tank set-up.

Just a thought.