Westerbeke 4-91 Injection Pump Leaking

[sanibel sailor]

Originally Posted by MDR_Sailing

Thanks gentlemen, it looks like I've located it in the photos below. I'm pretty sure that is where the leak is originating, I'm getting a drop of diesel every 10 or so seconds at the lowest point of the pump. All the other fittings/hoses seem dry.

It looks like I have the 12pt bolts instead of the hex head bolts. Do you know which socket I'll need for removal here? I think you mentioned it being a little difficult to find.

Is the o-ring that will need replacing pretty easy to locate once I remove the two bolts and pull the throttle shaft?

Not to be harsh, but you really should read prior posts in this thread, especially 13/19/26 et al...

Short answer - 1/4" 12 point socket. I could not source it locally and bought off eBay for a couple of bucks. O ring is obvious, see prior pics.

[sanibel sailor]

BTW, welcome to CF, hope you will stick around once you fix your leak.

[MDR_Sailing]

Thanks John, just wanting to double/triple check every question I have before taking anything apart. I appreciate both of your help, these Westerbeke's can be a little tricky to work on/locate parts for.

[MDR_Sailing]

One last question before we open her up this week. Do you know of any torque settings for the two twelve point bolts? I want to avoid breaking anything on the reinstall

Thanks again for the help!

[sanibel sailor]

I do not have the torque specs. Bolts are hardened and case is aluminum, but they have long threads, so I would just use standard torque specs per bolt size which I would guess is a 3/16" or #10.

[Capt Gill]

Just what I was looking for ! Although I have much experience (having owned a auto mech. shop) I've never dealt with mechanical f.injection, esp. CAV diesel pumps. Prior to searching CF I kept hearing,when describing my fuel leak issue(narrowed down to be somewhere from above throttle shaft housing gasket, don't mess with the pump it needs to be done at a specialized shop that has the many special tools needed for repair and calibrating - mostly true. Also, there was a lack of detailed info describing the pump,even the shop manual for my Perkins 4.108M had v.little info. So, thanks to the CF posters who seem to have similar attitudes regarding caveats,e.g.,"To be performed only at an authorized repair facility","No trespassing" and "Do not open,no user serviceable parts inside" and treat it as only advisories leaving it to their judgement whether or not to proceed. That said, I'm in the process of replacing the seals on my throttle shaft after which I'll post the results.

[sanibel sailor]

Always happy to lead another sailor astray

[marvinjansen50]

Mine is still working great n not leaking. Thanks to all the help and trying to find cheap n simple solutions. Now working on a bigger 200hp Volvo Penta tamd41p-a in a new fishing boat.

[jason1903]

I had this problem, exact same pump as pictured in post #29. Replaced the o-ring, put it all back together but now I am not getting fuel to the injectors. I bled the system, plenty getting to the pump but that's as far as it goes. I have a couple of ideas, but wanted to get some input before diving back in...

First of all, there are the two holes that pass through the shaft in the groove towards the bottom (as can be seen in the pictures on post 29). Do these need to aligned in a certain direction? The shaft swivels freely, so perhaps I need to line those up properly?

The other idea is that the shaft is getting stuck in the up (kill) position. I checked for burrs or any other possible obstructions but saw none. However, when I pushed the plate at the bottom of the spring up to test the two levers I noticed that sometimes it caught. Maybe it is not seating properly and is thus creating drag on the shaft?

If anyone has some input or new theories it would be greatly appreciated.

[CS Cruiser]

Great input guys thanks for sharing, I'm in need of replacing those o-rings as well (throttle side) and have been putting it off since it wasn't clear to me how the shafts were removed.

[sanibel sailor]

Originally Posted by jason1903

I had this problem, exact same pump as pictured in post #29. Replaced the o-ring, put it all back together but now I am not getting fuel to the injectors. I bled the system, plenty getting to the pump but that's as far as it goes. I have a couple of ideas, but wanted to get some input before diving back in...

First of all, there are the two holes that pass through the shaft in the groove towards the bottom (as can be seen in the pictures on post 29). Do these need to aligned in a certain direction? The shaft swivels freely, so perhaps I need to line those up properly?

The other idea is that the shaft is getting stuck in the up (kill) position. I checked for burrs or any other possible obstructions but saw none. However, when I pushed the plate at the bottom of the spring up to test the two levers I noticed that sometimes it caught. Maybe it is not seating properly and is thus creating drag on the shaft?

If anyone has some input or new theories it would be greatly appreciated.

probably the kill plunger sticking in the bore. Happened to me. You figured it out a lot quicker than I did. If the throttle housing is tweaked a bit, it binds. mine was also assembled dry. Lubricating with a little diesel fuel helped considerably. After all, they do call it fuel oil.

[Capt Gill]

I've finally finished replacing the seals in the throttle housing. In my case I left the pump in situ and removed the housing, a few fuel lines,coolant hoses and the oil filter w/adapter for access. One can see from the photo that the bore is scored,but not so much that a bit of honing (used a Dremel tool and a small piece of 3M green sanding pad)would clean up nicely. Please note this engine is a Perkins "New" 4.108M. It took so long due to reasons with which you may be familiar,i.e., "since I have all this access I may as well clean this,replace that and so on". All back together, bled the system except for the injectors by ticking the lift pump then blocked the intake (there's no compression release,but this has similar effect) and bled the injectors with a few crankovers
via the starter motor. Yea ! No leak. Didn't buy the seal kit,used locally sourced "O" rings.

[Capt Gill]

The photos (I hope). BTW, I used a 1/4" 12pt box wrench,height limitations precluded the socket.

[sanibel sailor]

Great news.
Looking at the last pic, you really need to be careful to keep all the crumbly crud out of the innards.
BTW- where did the exploded diagram come from? I have never seen that one.

[Capt Gill]

Originally Posted by sanibel sailor

Great news.
Looking at the last pic, you really need to be careful to keep all the crumbly crud out of the innards.
BTW- where did the exploded diagram come from? I have never seen that one.

I knew someone would ask that question and wish I could give the answer,sorry. I was doing much searching during that time,it may have come from the link you posted for the ebay seal kit -not sure. This is how I filed it, DPA REG HYDRO SealKit.png, if that's any help. Yes,the crud you see in the photo is one of the projects I mentioned as "to do"while I have access.