871 Fuel Pump

[Fredward]

As long as I have the engine out I'm going to replace the fuel pump. It's an 871 in an MC-5 so it's a right hand rotation engine. It looks like the Detroit pn is 5199561R. Does that seem correct?

I recall but can't seem to find a thread here about replacing the pump drive coupling at the same time? I see a Fuel Pump Coupling and a Fuel pump coupling fork and a fuel pump seal on the DieselPro web site. Should I order any of those items?


Fred

[luvrbus]

Good idea to replace the fork I never saw the drive fail before all fuel pumps on the 2 strokes turn left on either rotation of the engines the L and R marked on the pumps identifies the suction side look and see which side the little arrow is located on yours and order that one, if yours is not seeping I wouldn't bother with changing it but if you do change go with the hi volume or a DDEC pump 

good luck

[wg4t50]

Do not forget to check the dog bone that drives the blower & fuel pump, when the teeth get stripped the blower stops along with the fuel pump, gets real quiet.
Dave M

[Fredward]

Where is that located ?  I'm changing the blower drive boot also.


Fred

[bevans6]

You know that 4 " diameter tube between the back of the blower and the rear engine plate?  The blower drive shaft is a 1" or so diameter shaft splined on both ends that runs inside that tube.  It can be removed after you take the cover plate off over the blower drive gear.  You need to remove it anyway if you change that tube the way Clifford wants you to.  Inspect the splines closely with a magnifying glass, look for wear or twist.

Brian

[Fredward]

Oh THAT dogbone. !! Gotcha. Turns out the alternator drive pulley is kinda in the way.


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[luvrbus]

It is behind the plate that has the 6 bolts looks like it comes of easy

good luck

[Fredward]

Yah that pulley gets in the way of the bottom right hand bolt. I'll have to get creative.


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[bevans6]

What's that big spring thing hanging down beside the pulley?  Mine doesn't have one.  I suspect part of the clutch mechanism?

Brian

[Fredward]

Yes. That's a clutch return spring. I have now removed it along with the compressor that I'm replacing as a part of the project.


Fred

[bevans6]

Interesting.  I was going to ask if I could get it from you but I remembered that I have a clutch return spring but at the front end of the linkage.  I need a lighter pedal, not a heavier pedal from an extra spring!  Above it there is a pivot looking thing on a cast iron mount.  What is that for?  Mine doesn't have one.

Brian

[wg4t50]

Looking at that picture brings back many learning thoughts about the MCI setup of that vintage, notice the SAE I bolt pattern on the housing, then notice how far the starter bendix is mounted inward with a very small hump on the outer side at the motor mount, that is due to the flywheel being a SAE 2.  OH how do I know that bit of crap, yup been there when tying to put the Road Ranger RTO910 on the MC7. In the end, got it done, but required the SAE 2 Spicer clutch Duel Disk type, than an adapter ring bolted to the SAE 1 bell housing, and a SAE 2 Housing on the Road Ranger.  Reason for the adapter ring, that MCI version SAE 1 bell housing is too shallow, so the ring was used as a spacer, then it all came together and worked as expected.
When went with the 12V-71, changed transmission housing to the SAE 1, stayed that way up to and including the 8V-92.
Like mentioned, lots of memory flash backs, some sweet, some big learning, some just strange, but in the end I had a wonderful great time, spent a lot of money, but never counted it.  Who cares.
Dave M

[Boomer]

If you change the blower drive shaft (quill shaft) you should update to the coarse spline shaft & drive which is 29 spline, they never strip the splines whereas the fine splines will on occasion strip and leave you stranded.  I have had it happen twice, once on a 12V and once on an 8V albeit over a 40 year span of operating 2 strokes.  Just a tip, HTH.