Lift Pump-Perkins Range 4

Question: Do the lift pumps used on Perkins engines have a 1 way check valve, so as to keep fuel from backflowing when bleeding and I keep pumping the lever, or do these systems bleed like you would brakes on a car, apply pressure, open the bleeder valve and repeat?

I have looked at previous posts and it appears both methods may have been used. Having difficulty getting fuel to the engine filter (vent on top of housing cracked open) before the CAV pump. My first time doing and a bear, to be polite!

Any tricks, other than a primer bulb or electric pump?

Appreciate the advice. Thanks!

My 63544s are bled simply by pumping the lever, so there must be a check valve. Make sure that the lift pump actuation lever is on the flat spot of the cam lobe. If the lever is on the top of the lobe, the diaphram will already be stroked out, so pumping the hand lever will have little effect. Try rotating the engine a bit to see if you get more stroke on the priming lever. Keep moving the engine until you get maximum stroke. I've had a lift pump go out showing the same symptoms, but once I got the engine bled, it ran fine. A full fuel tank will help fill the fuel filter too. Last resort, you could hand fill the filter with known very clean fuel, as any contamination you poor in will bypass the filter. The lift pump is actually a very comon pump on older english cars, and if you take it to an auto parts store, they may be able to provide an exact duplicate, or one with minor differences.

Sorry...I know you said "other than an electric pump" but I couldn't help myself.

To my benefit, the PO installed small 12V boost pumps inline before the Racors. I can activate a momentary on switch wired remotely to bleed the filter and pump. I needed to use it today after replacing a weeping elbow at the lift pump. It's almost effortless.

If my lift pump(s) fail, I'll use the boost pumps to the provide the low fuel pressure.

Every on engine lift pump has check valve. They wouldn't work otherwise. But I think that Artic Traveler has the solution: rotate the engine so the cam is down and not up all of the way limiting your ability to stroke the pump.


And FWIW, if you have to do this a lot, consider adding a squeeze bulb primer. Tony Athens sells one on his sbmar website with all of the fittings in a package: Squeeze Bulb Priming Kit - Seaboard Marine


David

FlyWright, having this be my first attempt bleeding with the lift pump, it may be my last! The more I read and try to bleed, the electric pump seems to make sense. Many newer engines use electric pumps as the only fuel delivery pump, so reliability should be good. Besides, I don't travel very far!

In reading the Dahl filter manual, they also have a check valve to stop back flow, so I guess is a moot point.

Thanks!

Goldenstar38 said:

FlyWright, having this be my first attempt bleeding with the lift pump, it may be my last! The more I read and try to bleed, the electric pump seems to make sense. Many newer engines use electric pumps as the only fuel delivery pump, so reliability should be good. Besides, I don't travel very far!

In reading the Dahl filter manual, they also have a check valve to stop back flow, so I guess is a moot point.

Thanks!

Click to expand...

We replaced the mechanical lift pump on our Perkins 3.6544M twenty years ago for a Walbro electric pump and carry a spare one as well. Makes changing filters a dream.......

If your lift pump is working correctly, you should have no problems bleeding your engine, but it takes quite a few strokes to fill the filters. Try loosing the inlet line to the filter to check the flow rate. I do wonder why you need to do this so often though.

Arctic Traveller, This is my very first time doing this since I purchased the boat 2.5 years ago. Never had any starting or running issues before I did some fuel tank maintenance and the replaced primary and secondary filters.

The primary filter housings were filled with clean diesel per the Dahl manual, same with the secondary filters. Never touched any other fuel line fitting. Just having a difficult time bleeding. I had read the Perkins can be tough to bleed. Seems they were right!

Goldenstar, do you have the step-by-step guidance of the maintenance manual? It addresses the sequence of bleeding filter, hi pressure pump (I think you have 2 bleed screws there like my 4.236's) and the injectors?

I've never had any problem bleeding mine except when the lift pump was worn out. The engine ran fine, but the pump wouldn't fill the filter. Once I got a new pump, it filled quickly. As I said, the pump was inexpensive when purchaced at an auto parts store instead of Perkins.

If just the filters were changed, bleeding the injection pump and injector lines shouldn't be needed unless the engine was cranked over a bunch. Good luck

Yes, I do have bleeding instructions. Based on my degree of difficulty thus far, I am questioning the lift pumps functionality. Their paint matches the engines which do not appear to ever have been painted.

I'm going to plug along a little longer. If issues remain, will investigate new lift pumps. Thank you so much for your help.

After spending some time after work trying this again, I highly suspect the lift pump is worn. I noticed there is little pressure on the pump stroke until neat the top 1/4 of the arm lift. This seems to follow Arctic Travellers issue, where the engines ran fine, but could not bleed properly. Given their apparent age, I believe I will research new lift pumps, or, again consider adding electric pumps to both engines.

I again appreciate the helpful comments.

Last question. IF using electric pumps, being I have 2, 1985 Perkins Range 4-200 turbo engines, I assume the volume should be about 35 GPH at what pressure, 7 PSI? Thought this would help narrow down my search parameters.

Goldenstar38 said:

Last question. IF using electric pumps, being I have 2, 1985 Perkins Range 4-200 turbo engines, I assume the volume should be about 35 GPH at what pressure, 7 PSI? Thought this would help narrow down my search parameters.

Click to expand...

That is the pressure of the pump we use.
Here is the pump we use.

I just transferred 40 gals of fuel this week to one tank...then back to the original tank for a repair. My little wobble pumps moved about 16-20 gph. That's a lot of fuel for my little 4.236 and possibly yours, too.

Here's a pic from another project that shows a brass color pump with wires disconnected.



I'm not sure how much flow is required above and beyond consumption for cooling and lubrication purposes. Many here are much more knowledgeable about this than me. I look forward to the discussion. I'm very interested.

Goldenstar38 said:

I noticed there is little pressure on the pump stroke until neat the top 1/4 of the arm lift.

Click to expand...

Thats exactly what it feels like when the pump arm is on the high point of the cam. If you haven't already, just bump the starter to turn the engine over about half a turn (watch the crank pulley) and see if you get more stroke.

The lever has quite a bit of travel up and down, so it seemed to be on the low spot, but I will try again later today on break. Guess I thought if on the high lobe, it would have no travel.

Goldenstar38 said:

The lever has quite a bit of travel up and down, so it seemed to be on the low spot, but I will try again later today on break. Guess I thought if on the high lobe, it would have no travel.

Click to expand...

Nope, the hand lever travel is the same no matter where the cam is.

The first time I operated the lift pump lever, I found I wasn't moving it to its fullest reach. Once I was directed to swing the lever fully to the limit, it worked much better. Maybe that's your issue here?

Arctic Traveller, I guess I mistakenly assumed that the lever travel would be different. Now, that makes sense now. I will bump the engine and try again. Also, I should feel resistance all the time through the whole pump stroke, correct? I only had a slight resistance at the top of the upwards stroke before. Really appreciate the input, as this is all new to me, being a former gasoline engine boater!

Well, I just spent 32 minutes after work (I live aboard and work from home) trying to bleed by port engine (easiest to reach lift pump and CAV pump) and I don't know how to say this....But,.. I love you guys! Easy to bleed with the lift pump (in the right position!). When done. mopped up fuel and she fired right up! Zero crank, just started like a Perkins should.

Again. my sincerest THANK YOU ALL!

Made my weekend! Now, tomorrow, tackle the starboard engine. Piece of cake now!

Is your thumb sore?

Not as sore as it was from the past 2 days! Actually, today was a smooth time. I'm so happy, doubt I would feel any pain!

There's a nice sense of satisfaction when we solve a problem and get something working. Good job............

Arctic Traveller, thanks to your and others input, this was an easy fix! Now, finish the starboard engine tomorrow.

If a search brings this up,

The key is to install a $50 inline fuel pump, powered up when the ignition is keyed on.

I spent 1.5 hours, a bloody finger and angst because I didn't know I had this previously installed by PO. The pump lets you prime filters, clean out fuel lines, and (with a T installed to show proof the fuel clarity) which makes the SO mucho happy.

The sound of the Brrrrrrrr of the electric fuel pump is comforting (and cheaper) than worrying about the original fuel lift pump.