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Old 03-05-2015, 04:44   #16
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Re: Perkins 4108 air leak?

I had a problem with my Perkins and after considerable time found it by temporally replacing parts of the fuel hose with clear. You can see the bubbles and trace the leak back to the guilty part. It was a gasket gone bad in the electric fuel pump.
Bob
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Old 03-05-2015, 07:19   #17
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Re: Perkins 4108 air leak?

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Originally Posted by Capt Gill View Post
Volvo boat engine ? Diesel ? Elect. high press. pump or lift pump ? I'm not sure what you're saying here, seems like you're confusing the lift pump w/the high press. injector pump.
Jack
Sorry to confuse you Jack - Diesel, lift pump. I thought this was a Cruiser;s forum for boaters so I didn't know it was necessary to say "boat". Also, in case of any confusion - the lift pump is sometimes called the "primary" and works on a cam on the side of the engine - its just below the secondary fuel filter (the one on the engine). The high pressure pump is on the other side of the engine and provides pressure to the 4 injectors. The injectors have two lines (one from the high pressure side and one leaving from the top of the injector (fuel overflow return) -they should all be routed back via the fuel return line to the fuel tank directly. Some are also fed back to the secondary fuel filter (on the engine) but they can cause problems if they get air-locked. I guess the idea Perkins had here was to be sure any crap from the top of the engine injector was filtered again.
I just recently pulled all the injectors and pumps (after 19 years) and had one injector that was not working and one other that was in dire need of a new nozzle. I worked for a month and a half - overhailed all the engine pumps, seals, rubber hoses, Bowman classic water jacket rubbers, the tubestack and the alternator. One interesting note - the water pump (which is a Jabsco 3270-0001) impeller had been in the engine for 19 years - never had to be changed out - but it WAS time ! I think its longevity was due to the "speedseal" which I installed on the pump (replaces the cover plate that holds the impeller in place) at a cost of $149 (from England) about 18 years ago. They really ARE worth the cost AND are real easy to remove - all it takes is a bit of thumb and index finger pressure to unscrew the nice big knurled knobs on the 4 screws.
And BTW - the "index" finger is the one between the thumb and the middle finger (count your thumb as a finger) - just in case you guys/gals in CA have more than five per hand :>)
The other reason I think why the impeller lasted so long was the fact that Canadian water temps are MUCH lower than southern waters, have less salt and the engines run much cooler than in the south. Last year was my first trip south so the warmer waters took their toll on that rubber impeller.
This temp diff due to diff areas of the globe I have noticed sometimes causes arguments between some people on the subject of Perkins 4-108 running temps ! Probably other engines too.
Have a GREAT ONE and I sometimes take a BIG swig of Bahamian Rum with Pineapple juice if I find I'm getting confused :>)
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Old 03-05-2015, 20:57   #18
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Re: Perkins 4108 air leak?

Quote:
Originally Posted by northiceman View Post
Sorry to confuse you Jack - Diesel, lift pump. I thought this was a Cruiser;s forum for boaters so I didn't know it was necessary to say "boat". Also, in case of any confusion - the lift pump is sometimes called the "primary" and works on a cam on the side of the engine - its just below the secondary fuel filter (the one on the engine). The high pressure pump is on the other side of the engine and provides pressure to the 4 injectors. The injectors have two lines (one from the high pressure side and one leaving from the top of the injector (fuel overflow return) -they should all be routed back via the fuel return line to the fuel tank directly. Some are also fed back to the secondary fuel filter (on the engine) but they can cause problems if they get air-locked. I guess the idea Perkins had here was to be sure any crap from the top of the engine injector was filtered again.
I just recently pulled all the injectors and pumps (after 19 years) and had one injector that was not working and one other that was in dire need of a new nozzle. I worked for a month and a half - overhailed all the engine pumps, seals, rubber hoses, Bowman classic water jacket rubbers, the tubestack and the alternator. One interesting note - the water pump (which is a Jabsco 3270-0001) impeller had been in the engine for 19 years - never had to be changed out - but it WAS time ! I think its longevity was due to the "speedseal" which I installed on the pump (replaces the cover plate that holds the impeller in place) at a cost of $149 (from England) about 18 years ago. They really ARE worth the cost AND are real easy to remove - all it takes is a bit of thumb and index finger pressure to unscrew the nice big knurled knobs on the 4 screws.
And BTW - the "index" finger is the one between the thumb and the middle finger (count your thumb as a finger) - just in case you guys/gals in CA have more than five per hand :>)
The other reason I think why the impeller lasted so long was the fact that Canadian water temps are MUCH lower than southern waters, have less salt and the engines run much cooler than in the south. Last year was my first trip south so the warmer waters took their toll on that rubber impeller.
This temp diff due to diff areas of the globe I have noticed sometimes causes arguments between some people on the subject of Perkins 4-108 running temps ! Probably other engines too.
Have a GREAT ONE and I sometimes take a BIG swig of Bahamian Rum with Pineapple juice if I find I'm getting confused :>)
I hesitated a bit in asking what should have been obvious, boat or car, but in the interest of clarity I added it.
I'll be getting a little off the thread, although the focus will be the 4-108 which is the engine installed on my boat(Perkins refers to it as,"New"4-108M", that I've owned since 2007 and have put many hours since, a robust engine, more so than the ubiquitous Yanmar in my opinion. It's been a mostly a good relationship and gets better with familiarity. Thank you for elaborating on your post, that is helpful.
The only issue of note has been raw water intrusion in the coolant - twice - same place. The second time I was much more thorough as salt water really mucks things up requiring time consuming proper flushing and I didn't want to do this again, I also felt this as a reproach from Ms Perkins for some oversight, so I needed to set things right. Being the later "New" 4-108 it has the neoprene end caps sealing the heat exchanger's raw water intake and outlet from the engine coolant, two hose clamps on each end the larger one clamps the cap to the coolant reservoir, the smaller to the heat exchanger, it was the later where the leak occurred both times. I measured the length of the exchanger and compared that to the length of where it is to be installed,i.e., on each end cap there is a shoulder where its ID is reduced to the OD of the exchanger, my measurement was from shoulder to shoulder. I found the difference to be v.small, not much for the clamp to grab,so the exchanger must be exactly centered, then roughed up the exchanger ends a bit for better holding, tighten clamps securing exchanger a little at a time alternating from one to the other (v. important so as not to squeeze the bugger out of place) until secure then retighten after running engine awhile. I went as far as to (before hooking hoses to end caps) install a pressure gauge at one end a tire schrader valve at the other put about 40 psi air pressure and left o'night -all good. Now, why didn't they add a little more length to the exchanger or maybe mine was an aftermarket replacement I don't know. Also, there's barely anything said regarding the later style exchanger in the OEM shop manual nor could I find much in the net. This is my two farthings worth.
Jack
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