rebuilt yanmar engine , wont start

jd4310man · Jul 9, 2017

I just got a yanmar 3tnv82a put back together and it doesn't want to start. I get a few puffs of white smoke but thats about it. I had the block and head re-done, new pistons and rings, all new main bearings, rebuilt injectors, I got the timing gears all lined up and everything torqued to spec. Only thing is im not sure about the pump itself, I put it on the timing marks that line up the pump housing and timing cover. The injection pump is flowing fuel. Kinda got me stumped, any ideas?

thepumpguysc · Jul 10, 2017

Did you have a book?? did you follow it to the letter on the inj. pump install? on the back side of the inj. pump is a stamped dimension for the timing "lift".. set w/ a dial indicator..

jd4310man · Aug 7, 2017

I Got the engine to run but is real hard to start, blows lots of bluish-white smoke that smells like un-burnt fuel. Also it wont run much past idle. I still think its an timing issue. I don't have the knowledge, tools or experience to know what to do. It idles pretty good, but like I said it smokes.

CalG · Aug 7, 2017

If it runs at all, One simple diagnostic is to crack the fuel supply fittings at the injectors.
Letting off the pressure of a "running" cylinder should cause the engine to stumble. The same pressure let off of a non running cylinder will show no change. Heck, just bleeding air out of the lines again may be a help.

But if you are "blowing white smoke" it's dollars to doughnuts that you have a pot that's getting fuel but not hitting. Are the valve lash setting correct to get a tight seal?

It sounds to me like you were not the most qualified person to do the rebuild, and now you need to come up to speed. Aren't these boards great!

jd4310man · Aug 8, 2017

Your right, Im Not the most qualified to do a rebuild. Im not a mechanic by trade, just a guy who needs stuff done and cant afford a mechanic all the time. That being said, I had the block and head sent out and re-machined, all new pistons and rings, new main bearings, all new gaskets. Everything is torqued to speck. Im pretty sure its the injection system thats the problem. I also had all 3 injectors rebuilt.

CalG · Aug 8, 2017

jd4310man said:
Your right, Im Not the most qualified to do a rebuild. Im not a mechanic by trade, just a guy who needs stuff done and cant afford a mechanic all the time. That being said, I had the block and head sent out and re-machined, all new pistons and rings, new main bearings, all new gaskets. Everything is torqued to speck. Im pretty sure its the injection system thats the problem. I also had all 3 injectors rebuilt.

Ahh! Rebuilt injectors. One more piece to the puzzle. That can be good, or it could be an unknown. Did you get a test report of any kind with the rebuild. Popping pressure and spray verification.

Do you feel you have all the air out of the lines from tank to injectors?

When the fuel delivery pump was installed, did the "timing shims" go on just as they came off? How did you confirm that things have been put together and timed correctly. Marks on the cam and engine sprockets? Reference lines etc. I don't presume to know the details of how this engine is assembled, but You were just there. Is there anything that makes you wonder or worry? New or rebuilt parts are one thing. but they need to move as one. Assembly is in the details.

jd4310man · Aug 9, 2017

I had my local injection shop do the rebuild. Im pretty sure all the air is out of the lines as it is puffing white smoke on first cranking of the engine. This yanmar doesn't use shims, the pump is seperate from the block. Here is a link to the shop manual that describes the timing. http://storage1.fermer.ru/bocu/93778/tnv.pdf Look on page 61,62. The only thing im not 100% sure on is the valves as they were ground by a local machine shop. The owner assured me that they are fine. So thats why I believe that its the timing. Upon reassembly, I mounted the injection pump and aligned the factory marks. I believe that those marks are a starting point and not a final timing position.

thepumpguysc · Aug 9, 2017

Did you remove the pump flange from the drive gear?? IF NOT, then the pump will only go on 1 way.. the key has to line up w/ the pump flange.
& the flange is bolted to the drive gear.. the drive gear has slots for final timing adjustments..

JohnDeere575Jeff · Aug 12, 2018

What ever happened with this engine and project?

thepumpguysc · Aug 12, 2018

Jeff, the thread is over 1 year old.. I sure hope he got it going by now.. but ya never know..??
I HATE those pumps & I do this for a living.. Biggest, over priced, piece of crap that was ever put on an engine..
Its so over-engineered, Yanmar cant tell you how to put it on or time it..{engine rebuild manual}