06-30-2012, 09:01 PM
Fuel injection and timing issues with 404 engine in 4630
We have been working on this tractor for a while now. Planting and taking care of hogs or other things has basically kept us from finishing for over 2 years. Finally we got around to getting a replacement motor because the one that we had just rebuilt dropped a valve and and pieces of it went flying around thru the exhaust into other pistons so with the new motor off a old jd combine, we dropped it in place, got everything back together and ran it. The pump was smaller and everything was backwards for throttle and kill switch so we took the roosa master off and put the bosch on only to find out that the block on the engine had different size injector hole threads since the bosch uses different injectors and lines so everything had to be taken off that was fuel related and switched back to the roosa master injector rotary pump. I got everything timed just as the stock bosch pump would be with top dead center and the two timing marks on the pump lined up although you have to take a little plate off on the side to see the marks. When we went to start it, it wouldnt do anything without spraying either even though all the lines were bled all the way up to the injectors. Finally when it did, it blew smoke the whole time and wouldnt run at idle speed. My guess is that it might possible need advanced because the mark in the pump that was suppose to be stationary i thought moved a little and that could have caused timing to be off. Just for information if needed, the replacement motor (404) came off a 6600 jd combine while the orginal tractor is 4630 which has had the motor rebuilt twice on it before (one of the times we did and as i said, it dropped another valve just like it did before so wegave up because the timing was all perfect...) The replacement motor was run several times and performed flawlessly before we tried switching to the bosch pump. So basically, this is a timing issue or maybe the injectors are air locked because everything else was bled... Thanks for any help or advice.
06-30-2012 09:01 PM
07-02-2012, 10:01 PM
I am guessing you might have the pump 180* out of time. TDC on the crankshaft could be for #1 or #6 cylinder. The only way to tell for sure is to pull the valve cover off and check the valves when the timing pin engages the flywheel. If you ar on #1 TDC, the front three rocker arms should all be loose(.018" clearance on intake and ".028" on exhaust). If the rear three rockers are loose, then you are on #6. If it is installed incorrectly, remove the pump and turn crankshaft one complete revolution and the reinstall the pump.