Yamaha generator valve adjustment


(Arthur Pappas) #1

I’ve never done a valve adjustment before and I need some help. Too many 2 strokes I guess.

I’ve got the valve cover off our Yamaha EF4500ISE generator but I’m not quite sure how to proceed.

Are the valves supposed to be at a certain position when I check the clearance? I can ‘tick’ the engine briefly and move the valves but am not sure if it matters where they land (both up, one up and one down, etc.).

Where exactly am I supposed to check the clearance? Where the arrows are pointing? Right now there doesn’t seem to be any clearance. Am I supposed to loosen the nuts (on top) first?


(Clayton James William Walker) #2

The engine needs to be at tdc. Usually there are marks on the cam. Yes slide the gauge in where you are pointed . Loosen the lock not and use a screw driver to adjust the gap. It looks just like a ktm rfs engine.

Look it up on you tube prolly be best then you see how to find tdc
You may have to drain the oil to do it.

WHY are you checking valves. Seems overkill unless it has like 50? 000 hours.


(Clayton James William Walker) #3

You need to determine the gap before you loosen the nuts.


(Arthur Pappas) #4

Thanks – got it figured out. Unit has just under 4,600 hours.


(Jon Mutiger) #5

Looser is better than tight too, especially if it was exhibiting hard to start when hot problems


(Arthur Pappas) #6

Thanks. The issue I’m seeing is that it is hard to start when cold. The unit is equipped with an electronic choke that doesn’t seem to be doing its job. Replacing the ECU costs half as much as buying a new unit. Just another way corporations force obsolescence.


(Clayton James William Walker) #7

So Jon. To get this straight you would take your engine apart to purposely adjust the valaves pout of spec?


(Arthur Pappas) #8

Meow Meow didn’t say out of spec, he means the loose side within the spec.


(Clayton James William Walker) #9

No he means out of spec.