4-71 startup

[mudfarmer]

Still learning about the screaming jimmies--took an all expenses paid trip to Detroit for a day   did rubber & steel o rings in a 4-71 head which fixed coolant in oil/ oil in exhaust and cleared up smoke on startup.

One "problem", it takes a little jiggle of the throttle to start up. Never did that before  ??? rack timing checks out perfect by the book, idles and runs perfect, wondering if you all have any thoughts. Found one steel fuel line with a pin hole worn from mount and fixed that.

Thanks in advance

[moodnacreek]

Another screamin green 'Yamaha' 2 stroke. Get yourself a real diesel; a pony start Cat, now you got something. :D 
                                   

[moodnacreek]

Darn it, that got posted. Just kidding Mud Farmer, I like both.

[mudfarmer]

 :D :D

Thanks, not mine so no harm no foul, don't care if you call it a gutless stinky leaking sack of ---- just want to get it 100% for him. Will go back through the tune and see if I missed something. Governor gap and buffer I set by the book maybe I did something out of order.

[snowstorm]

Did you have the injector height tool?. And the real Detroit manual? Something is not right

[quilbilly]

I'd always pump the accelerator on my 453s when starting. Not sure if I needed to or not, just seemed like they started quicker if I did. I sure miss those engines. Nothing like a jimmy. Never got to run a turbo powered joint but I heard it gave em a nice little boost in power and quieted them down to where regular ear plugs were all that was needed. 

[mudfarmer]

Snowstorm I used a real deal factory manual but only had the tail of a vernier caliper to use not the factory injector tool. Everything matched the book #s for the injectors that are in it

[C5C Tree Farmer]

If your 4-71 has a typical variable speed governor the injector racks are set in the full fuel position by the governor for starting. As soon as the engine starts the governor will adjust the rpm to the level determined  by the amount of spring pressure applied by the throttle lever.

Buffer spring adjustment controls the engine lope at idle.
Governor gap controls the governor response to the load applied.
The throttle position has no affect on the fuel rack position for startup.
The shut off cable manually overrides the governor and pulls the injector racks back to the no fuel position.

Raw engine oil in the exhaust ports can be caused by worn valve stems and guides. Excess crankcase pressure can cause engine oil to migrate along the valve stems.

[mudfarmer]

Thanks C5C Tree Farmer.

If throttle position has nothing to do with startup because the governor is setting rack to full fuel, however it will not start without a blip of the throttle, this makes me think maybe the rack is sticking/binding and when he is blipping the throttle that is allowing it to reset to full fuel? Seem to remember a comment that the shutoff pulls a little harder than it used to which would follow that path of reasoning so maybe the culprit and I will check it out later this week.

[C5C Tree Farmer]

That seems like a logical conclusion. I seem to recall that the use of the paper gasket was needed on the governor cover to provide the necessary clearance for the fuel shut off mechanism.

[mudfarmer]

Yes sir!

Pulled valve cover, every second or third time the shutoff is pulled the rack does not reset fully unless you pull the throttle after. Loosened the rack mount bolts and it worked properly. I do not know what he meant by shutoff pulls hard but don't know what it felt like before. The thick paper gasket was there.

Back to full Detroit, thanks for the help.8) Super simple problem that I overlooked on reassembly. Hope this thread helps someone in the future.