Yanmar mp4 4tnv98 help

[rmllarue91]

Hey hef im pullin my hair out tonight Got a 4 cyl yanmar. injection pump gear was removed and was given pump seperate from engine. They pulled four bolts instead of large nut. I reringed and resealed engine. When all timing marks are aligned for pump gear, crank and ,cam. the cylinder closest to timing cover both rocker arms are loose. Which according to manual is cylinder 4 and is on tdc. How do I know injection pump is on the right cylinder? I can measure the plunger to set precisely set timing with a dial indicator. But that could be on any of the four output lines if im understanding this. And once I firgue out where to have pump what cylinder does it fire to? Looks like cylinder 4 which is closest to timing cover if im reading this right. Thanks hef

 

[partsandservice]

Because it is a rotary pump it matters not which cylinder you time off of. When the plunger reaches specified lift this is where you would be looking for your advance. I seem to recall you have to get the number stamped on the injection pump, and aquire the F.I.R number and multiply by 2? To aquire the timing advance for that particular pump /engine set up. I take it you have the book?

 

[thepumpguysc]

If you google "Yanmar mp4 injection pump" scroll down & find manualslib dot com's write-up..
The manualslib wrt up is for a Doosan 4tnv98.
OR send me your email in a PM & I'll email you the manual.
The timing is CRITICAL on those pumps.
P&S> it wouldn't hurt you to take a peek at it too.. you HAVE TO KNOW the correct cylinder to time off of.
On every one I've ever done, the drive shaft & hub are keyed..

 

[rmllarue91]

Hey guys I got books from yanmar komastu and doosan even down loaded a book on mp4 just pump from yanmar. but they are almost identical. There is a keyed hub on pump but there's a gear that BOlts to that with 4 bolts that book says don't take out. When you get a new pump or rebuilt just leave hub with gear and you be pretty close. They took the bolts out. So you can bolt that gear to the pump in four different spots. Looks like one complete rotation fires all four cylinders on injection pump. I'm going to try to put fuel to pump and rotate by hand until I get fuel spilling for cylinder 1. Then install gear and set precise timing.

 

[partsandservice]

With the rotary pump it does not matter which cylinder you use to time off of. Same with the Bosch ve pump. The plunger comes up four times per two revs of the crank, so if you time it correctly off of any given cylinder the other three will be in time. I have been in this exact same situation with the same engine that someone else removed the pump hub. You cannot spill port time a rotary injection pump.

 

[thepumpguysc]

IF you look at the front of the pump housing behind the hub, theres the timing lines for #1 cyl. around the 9:00 area. they line up w/ the key.

 

[thepumpguysc]

SURE you can time a PUMP on any cylinder BUT the ENGINE has to be on the SAME cylinder!!

 

[partsandservice]

Yes those marks must line up, then the advance can timed off any cylinder. We would be on the same page much easier if we were having the discussion in person.

 

[thepumpguysc]

Lets go back & reread #1 post & #4..

 

[rmllarue91]

It's all good saved my butt thanks alot guys. Can't believe it don't mention that in the service manuals... Or maybe I missed it.

 

[rmllarue91]

I feel like one of them customers that just won't go away.... About 10 o clock there is a small hole that lines up with key in shaft on one of 4 positions the pump sits. I can't see any timing marks i'm going to up load a pic for clarification.

 

[partsandservice]

Pm sent.

 

[partsandservice]

If the pump was to be rotated 90 deg from figure 1 it makes no difference as number one port to number one injector is the same and in the same order. Pump gear and cam must have marks lined up for base timing. At this point what any cylinder that is coming up on TDC could be used to set the advance. There is a mark on the flywheel that corresponds to TDC. Once timing advance is calculated,. Measure the diameter of the flywheel and divide by 360. Multiply that by timing advance ,say 17 degrees, and make a mark on the flywheel . Rotate the engine in the direction of normal rotation coming into the advance mark , when your pump plunger reaches specified lift and your mark both line up at the same time you got it. Use the slots to adjust as needed.

Just put the hub on lined up with the key with the four bolts through the gear in the middle of adjustment slot. Gear mark timed to cam mark. Find the flywheel mark. The one I did I could not achieve the correct timing with in the slots and actually had to move the pump gear one tooth off the marks to get it to time properly. I has been running for two years now.

 

[rmllarue91]

Hey parts Service that's for your time I really appreciate it I got that part and measuring the lift I understand what i'm missing is the pump hub and gear are totally separate and the pump can be on one of the four cylinders just can't find the marks to set pump in right position to do timing

 

[rmllarue91]

Idk if i'm looking at this wrong but I think the pump needs to be on certain position to do timing

 

[partsandservice]

The gear is the only thing that had to be timed. I am not sure I am explaining well enough. The pump would have to be timed on an inline pump to flow time. You cannot flow time a rotary pump. Check your pm I have time today.

 

[Birken Vogt]

So I have a couple of these units out there. Have not had to do this procedure yet.

My question is, when you are using a dial indicator to check plunger stroke, it mentions some kind of special tool adapter. What is this and what do you do if you don't want to buy one?

 

[partsandservice]

I made a steel plate to bolt on and use a magnetic base dial indicator.

 

[Birken Vogt]

So the proprietary adapter that goes in the hole is just there to provide a solid base for the dial indicator? And a gooseneck or whatever will work with proper mounting, just stick the probe down the hole?

 

[rmllarue91]

Ten four your just measuring stroke if you have patience and three arms you can do it with slide caliper. I did with a mag base and a long stem dial caliber. You have to match pump cylinder to engine cylinder my engine doesn't have the mark to put pu.p in right position. I just hooked up fuel system rolled it over by hand watching the pump fire. Then matched 4 on pump to cylinder 4 on engine set the stroke on plugger to 2.5 mm and engine to 6 degrees btdc. Which might be retarded I got to double check what it should be but it finally runs. First time I had pump firing 90 degrees after each cylinder was tdc. It wouldn't run like that... The injection pump has 4 positions which is why I was 90 degrees out. Thanks for all the help I keep having to leave this job and couldn't ever get into completely