Yanmar Injector Pump

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May 11, 2005
3,431
Seidelman S37 Slidell, La.
Anyone have any experience on removing a Yanmar high pressure pump. While doing an oil change and general look over today, I noticed a very slight leak where the high pressure pump mounts to the block. ( 3GM ) This is a very, very slight seep, that looks to me more like oil than diesel. Appears there is a gasket or O ring under the mounting flange, that is seeping slightly. I checked the bolts and all are good and tight. So the question is, can I simply unbolt and lift up the high pressure pump, replace the gasket/Oring, and sit it back down without upsetting the timing or anything else.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
Anyone have any experience on removing a Yanmar high pressure pump. While doing an oil change and general look over today, I noticed a very slight leak where the high pressure pump mounts to the block. ( 3GM ) This is a very, very slight seep, that looks to me more like oil than diesel. Appears there is a gasket or O ring under the mounting flange, that is seeping slightly. I checked the bolts and all are good and tight. So the question is, can I simply unbolt and lift up the high pressure pump, replace the gasket/Oring, and sit it back down without upsetting the timing or anything else.
the pump you speak of has shims under the flange that preset the timing for the fuel to injectors....if you remove it i think it will come out ok fine...just dont change the thickness of those shimps...as for the gasket use silacon sealer on the shim boath sides ...when you put the pump back in the block there is a fork that the fuel rack stud has to go in be sure you get that lined up..... i have some shims here if you need one dou to yours being damaged .......hope this helps

regards

woody
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
Phil, no gasket there except for the timing shims. Probably is a slight weep from between the shims.. Don't know if I'd mess with it but if ya do, clean everything around there before pulling the pump and as Woodster says, the fuel rack engagment in the governor lever fork is the only thing to watch for. If you decide to seal the shims, use something very fluid for the sealant because if a goopy sealant is used, it may be trapped between the shims and increase the effective shim thickness... which would delay the timing.. If you use silicone, like Permatex high temp, use very sparingly and install quickly before it has time to skin over.. The only oil in that area is splash oil in the timing case.. (old timey gasket shellac might be the ticket there??.. Do ya have some left from assembling those old BSA scooters and trying to make them not leak?? )
 
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May 11, 2005
3,431
Seidelman S37 Slidell, La.
Thanks

I got this in the back of my mind to do at some future time, but is pretty far down the list of to do's. Looks like not too big a deal. From the slight amount of seepage, splash oil sounds correct. Claude, no more gasket shellac. But I have used a lot of it over the years on the limey oil leakers. Oddly enough, don't think I ever owned a BSA, but have turned wrenches on them. Have owned Triumph, Norton, AJS and even a Velocette once.
 
May 28, 2009
764
Hunter 376 Pensacola, FL
I'll be the first to admit I'm no expert on this issue, but it occurs to me that the shims are to control your injection timing, they're generally only a few thousanths thick, and adding any kind of sealant to them is going to add several thousanths additional thickness, which should have some (probably detrimental) effect on your injection timing. Additionally, I think any project that involves taking your engine apart without being completely sure what you'll find once you do cries out for purchase of a service manual. If you don't want to purchase one, there are several online that you can download. I think I found one here once: http://www2.burningzone.nl/engine/yanmar.html
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
NE use silver paint if you dont have any Indian head schelac that always works when in a pinch...

regards

woody
 
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