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BigAl.NZ 16-09-2019 19:09

Perkins 4108 High Pressure Pump Bleed
 
1 Attachment(s)
Hello,

It feels like Dejavu - I am in the situation where I need to bleed my Perkins 4108 again after the engine was starved of fuel.

I have primed with the lift pump the primary filter and fuel comes out. I think my issue now is with the High Pressure pump and exactly which screws need to be opened to bleed it.

There is a good guide here from TAD : https://www.tadiesels.com/assets/docs...20Changing.pdf

But the pictures are blurry and I suspect I have the later model of high pressure pump.

Mine looks like this.

Which screws should I loosen and in what if any order?

rbk 16-09-2019 19:26

Re: Perkins 4108 High Pressure Pump Bleed
 
Canít see which pump you have but looks like cav from a quick look. Low pressure union into the pump, side bleed screw, governor bleed screw and each injector line. Follow the fuel and tighten each as bubbles stop from low pressure to the injectors. Best to have an electric pump or someone else working the lift pump for the first bit then crank the starter once fuel is to the pump.

rbk 16-09-2019 19:28

Re: Perkins 4108 High Pressure Pump Bleed
 
Bad internet connection got a chance to see your pic. Donít touch screw 2. Just 1&3 as well as low pressure line in and injectors unions.

skipperpete 16-09-2019 19:45

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 2978264)
Hello,



It feels like Dejavu - I am in the situation where I need to bleed my Perkins 4108 again after the engine was starved of fuel.



I have primed with the lift pump the primary filter and fuel comes out. I think my issue now is with the High Pressure pump and exactly which screws need to be opened to bleed it.



There is a good guide here from TAD : https://www.tadiesels.com/assets/docs...20Changing.pdf



But the pictures are blurry and I suspect I have the later model of high pressure pump.



Mine looks like this.



Which screws should I loosen and in what if any order?



#2 is either the idle screw or max rpm screw so no need to loosen it but #1 and #3 are the governor and case bleed screws. Avoid overtightening the bleed screws, they break easily. In your photo it looks as though the stop control linkage/chain is under a bit of tension, best to make sure the little lever on the pump is happily sitting in the "run" position.
No particular order for bleeding but sometimes it's necessary to spin the engine over with those screws slightly open and let the internal vane pump spit out the air.

BigAl.NZ 16-09-2019 20:05

Re: Perkins 4108 High Pressure Pump Bleed
 
Awesome. I will have another go later in the week. I am a little suspects of things upstream towards the tank since it was a problem with the Racors that stopped for in the first place.

I might fully loosen the nut on the first filter and check that.

BigAl.NZ 16-09-2019 23:16

Re: Perkins 4108 High Pressure Pump Bleed
 
PPS: After servicing the racors, can they just be filled from the top with a jerry can? Refill to the top again?

BigAl.NZ 16-09-2019 23:18

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by rbk (Post 2978270)
Bad internet connection got a chance to see your pic. Donít touch screw 2. Just 1&3 as well as low pressure line in and injectors unions.

Where are the low pressure line in and injector unions? Are they in the picture?

skipperpete 17-09-2019 02:40

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 2978362)
Where are the low pressure line in and injector unions? Are they in the picture?



That's a good photo, you managed to capture all the relevant bits. The supply into the pump is the vertical pipe with blue paint on the far rhs that does a u turn. The hp pipes and unions can be seen behind the supply pipe. They are attached to the blackish horizontal extensions that are banjo bolted to the hydraulic rotor head.

BigAl.NZ 20-09-2019 15:48

Re: Perkins 4108 High Pressure Pump Bleed
 
Thanks all. Got motor to go but had to use some Enthanol starter fluid - ran great after that but would not start even after leaving the pre heater on for a few minutes.

Incidentially fuel gushed out screw #3. Hardly came out #1.

rbk 20-09-2019 15:54

Re: Perkins 4108 High Pressure Pump Bleed
 
Usually doesn't come out the governor vent very much, sorry I missed your other post. follow the copper line from the top of the on engine fuel filter to the HP pump, it enters above the HP injector lines. When replacing the on engine filter you can end up pushing air into the HP pump for a bit so cracking that line and getting fuel to the HP pump is a first step, then deal with the HP pump bleed ports.

rbk 20-09-2019 15:56

Re: Perkins 4108 High Pressure Pump Bleed
 
Also try using wd40 rather than ether IF you need some help starting, but you really shouldn't need anything. You will ruin your engine with ether.:danger:

rbk 20-09-2019 15:58

Re: Perkins 4108 High Pressure Pump Bleed
 
Your low pressure inlet is the furthest copper line on the right in your picture.

BigAl.NZ 20-09-2019 15:59

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by rbk (Post 2980898)
Also try using wd40 rather than ether IF you need some help starting, but you really shouldn't need anything. You will ruin your engine with ether.:danger:

Awsome - more great learning.

BigAl.NZ 20-09-2019 16:01

Re: Perkins 4108 High Pressure Pump Bleed
 
1 Attachment(s)
With the green arrow?

skipperpete 20-09-2019 18:25

Re: Perkins 4108 High Pressure Pump Bleed
 
1 Attachment(s)
Try and avoid the ether based starting aerosols, they can do harm unless it's done in subzero temperatureAttachment 200260

skipperpete 20-09-2019 18:27

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by skipperpete (Post 2980987)
Try and avoid the ether based starting aerosols, they can do harm unless it's done in subzero temperatureAttachment 200260



Oops , didn't mean to send 2 pics but it serves to emphasize the possibilities.

skipperpete 20-09-2019 18:56

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 2980902)
With the green arrow?



Yes, the green arrow. But there is one that is close to the rotor head on a very short stub visible too.

Marathon1150 20-09-2019 20:15

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 2978360)
PPS: After servicing the racors, can they just be filled from the top with a jerry can? Refill to the top again?

We have a 4.108 and a Racor 500 primary filter. I used to use a small bottle of fuel to top up the filter housing after changing a filter. Then I installed a small electric fuel pump to do that job. It will push fuel all the way through the secondary (on engine filter) which is helpful after changing that filter too. We had a problem with the Racor (plugged with fibres possibly from a paper towel left in the tank after I had it cleaned) and the engine quit because of fuel starvation. The small fuel pump would push fuel all the way through the HP pump bleed screws (we have a different pump than the one in your photo) and it was not necessary to crack the injector lines. The pump was about $20 and simple to install. Highly recommended. These are great engines but can be a pain to bleed.

BigAl.NZ 21-09-2019 12:51

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by skipperpete (Post 2980989)
Oops , didn't mean to send 2 pics but it serves to emphasize the possibilities.

Yeah, my brother knew that it wasn't something you want to do very often. The engine has only 4500 hours and always starts just great, but for love nor money after bleeding it with those screws and the injectors I could not get her to start.

I didn't bleed the line with the green arrow, but it was gushing out of screw #3.

BigAl.NZ 21-09-2019 12:52

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by Marathon1150 (Post 2981042)
We have a 4.108 and a Racor 500 primary filter. I used to use a small bottle of fuel to top up the filter housing after changing a filter. Then I installed a small electric fuel pump to do that job. It will push fuel all the way through the secondary (on engine filter) which is helpful after changing that filter too. We had a problem with the Racor (plugged with fibres possibly from a paper towel left in the tank after I had it cleaned) and the engine quit because of fuel starvation. The small fuel pump would push fuel all the way through the HP pump bleed screws (we have a different pump than the one in your photo) and it was not necessary to crack the injector lines. The pump was about $20 and simple to install. Highly recommended. These are great engines but can be a pain to bleed.

Tell me about it!!

Love to see a picture of the pump and where it is in your system.

Marathon1150 21-09-2019 13:02

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 2981441)
Tell me about it!!

Love to see a picture of the pump and where it is in your system.

hi: just sent you a PM. Good luck!

BigAl.NZ 21-09-2019 13:05

Re: Perkins 4108 High Pressure Pump Bleed
 
PS: It wasn't a particularly cold day, about 15 deg C - but we did try the Pre-Heater. How long should it be left on for before starting? (Not that it worked)

BigAl.NZ 12-01-2020 02:09

Re: Perkins 4108 High Pressure Pump Bleed
 
2 Attachment(s)
Dam it. We had a similar issue at the weekend. Fuel startvation (long story) and bleeding it seemed impossible (there seemed to be a lot of air coming out of #1 even after using the lift pump for some time.

It eventually started with "easy start" but I am nervous about using this.

I have gone over this thread again. Would someone please be able to label what A, B and C are?

Also what is the purpose of the pressure gauge between the two racors? It reads 0 when engine is running, and about 5 after engine has stopped (at least for a while.

Cheers

Al

skipperpete 12-01-2020 08:40

Re: Perkins 4108 High Pressure Pump Bleed
 
A is fuel in
B is an injector line nut
C is another injector pipe nut

BigAl.NZ 12-01-2020 10:53

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by skipperpete (Post 3054228)
A is fuel in
B is an injector line nut
C is another injector pipe nut

Thanks skipperpete. While the engine is going I am going to video the amount of fuel coming out of the injectors and with it not going but primed the amount of fuel coming out of the HP pump.

Then I will at least know how much to expect when the system is working.

For those people that fitted a primer bulb/pump - where in the fuel system did you put it?

Cheers

AL

Cheechako 12-01-2020 11:19

Re: Perkins 4108 High Pressure Pump Bleed
 
I never had to bleed the HP pump on my 4-108. I just cracked an injector and off it went. Then cracked each one until no bubbles while it was running. You couldn't keep my 4-108 from running. If you wanted to just turn the motor over a touch, it often started instead.

rbk 12-01-2020 12:27

Re: Perkins 4108 High Pressure Pump Bleed
 
Ours is in between our primary racor filter and the lift pump. Idea being any particulate is removed before fouling the pump. I would suggest going with a online fuel pump. They are around $50 usd and make it even easier than a bulb without the risk of a split bulb and a bilge full of fuel.

BigAl.NZ 12-01-2020 13:49

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by rbk (Post 3054381)
Ours is in between our primary racor filter and the lift pump. Idea being any particulate is removed before fouling the pump. I would suggest going with a online fuel pump. They are around $50 usd and make it even easier than a bulb without the risk of a split bulb and a bilge full of fuel.

What sort of online fuel pump is it? Though TAD said there is no need for it, I just can't seem to bleed the air out of this system.

jt11791 12-01-2020 14:32

Re: Perkins 4108 High Pressure Pump Bleed
 
The gauge on the Racor lets you the status of the filter. Normally with a good filter, it will read close to zero, maybe up to five. As the filter gets clogged, the vacuum level will rise and the gauge will let you know it's time to change it.

BigAl.NZ 12-01-2020 14:42

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by jt11791 (Post 3054471)
The gauge on the Racor lets you the status of the filter. Normally with a good filter, it will read close to zero, maybe up to five. As the filter gets clogged, the vacuum level will rise and the gauge will let you know it's time to change it.

Right. So over 5, time to change?

rbk 12-01-2020 17:33

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 3054444)
What sort of online fuel pump is it? Though TAD said there is no need for it, I just can't seem to bleed the air out of this system.

https://m.aircraftspruce.ca/catalog/...facetpumps.php

Makes bleeding a breeze and can act as a lift pump should your mechanical one fail.

BigAl.NZ 22-01-2020 10:54

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by rbk (Post 3054575)
https://m.aircraftspruce.ca/catalog/...facetpumps.php

Makes bleeding a breeze and can act as a lift pump should your mechanical one fail.

Yeah, after clearing our blocked fuel line from the tank, starting the motor on the good tank, I swap to the tank with the newly cleared fuel line.

Motor cut out, and after 100 pumps of the lift pump with primary banjo open, then 100 pumps of the lift pump with HP bleed valves open she still wouldn't start.

One of those facet pumps I think I will install!!

Marathon1150 22-01-2020 18:01

Re: Perkins 4108 High Pressure Pump Bleed
 
We installed an electric automotive fuel pump (very cheap, very easy to get, very reliable mounted inside the boat, very easy to install). This made life much, much easier whenever it is necessary to push fuel from the tank to fill up the Racor 500 filter housing after a primary or secondary filter change. It will also push fuel through the high pressure pump bleed points. I have not had to crack an injector since the installation so I don't know if it will push fuel that far through the system.

It is installed as a "branch" receiving fuel through a small valve that directs fuel from the tank, into the pump and then into the system upstream of the primary filter. I close the valve when everything is running normally to make it easier for the fuel to get directly from the tank into the system. However, I did forget to do this on one occasion and everything still ran normally.

BigAl.NZ 17-05-2020 23:32

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by Marathon1150 (Post 2981042)
We have a 4.108 and a Racor 500 primary filter. I used to use a small bottle of fuel to top up the filter housing after changing a filter. Then I installed a small electric fuel pump to do that job. It will push fuel all the way through the secondary (on engine filter) which is helpful after changing that filter too. We had a problem with the Racor (plugged with fibres possibly from a paper towel left in the tank after I had it cleaned) and the engine quit because of fuel starvation. The small fuel pump would push fuel all the way through the HP pump bleed screws (we have a different pump than the one in your photo) and it was not necessary to crack the injector lines. The pump was about $20 and simple to install. Highly recommended. These are great engines but can be a pain to bleed.

What pump did you buy?

Marathon1150 19-05-2020 09:08

Re: Perkins 4108 High Pressure Pump Bleed
 
Quote:

Originally Posted by BigAl.NZ (Post 3142138)
What pump did you buy?

It was a generic automotive gasoline pump - i.e. for a car. I was assured by the marine mechanic that recommended it that because it is built for gasoline it will meet all safety requirements for diesel. I went into an autoparts store in La Paz, Mexico and asked for an electric fuel pump. They provided me with an unbranded, new in the box pump. Mexico has a very large industry making autoparts for the North American auto industry etc. I would send a picture but the boat is in Tahiiti and we are in Vancouver with no idea of when we might get back there.


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