rlipsett

I have the older ys 63 engine with the regulator built in. the engine is mounted sideways with the tank mounted on the opposite side of a profile with so that they are mounted at the same hieght and almost literally together seaparated by the 3/4 fuse. the engine does not prime too easily with full open throttle. Easier to use the electric starter to pull prime. When running it is fairly good except for an occasional hesitation. I don't think it is tuning because a lot of the time I have no transition problems even when idliing for 30 seconds or more. tank pressure seems to bleed down a little when left for 1/2 hour or longer but it still has some residual just not as much if you pull it freshly after a run. looking for ideas.

ps I just checked the valves and they are gapped correctly and fully free moving

Four Stroker

Fix the pressure leak first. If not the plumbing, it's the one-way valve. Have you put a new diaphragm and plunger in lately ?

tande

My Feedback: (48)

+1

petec

My Feedback: (58)

The pressure leak could be caused by the one way valve. A bad check valve will give you fits.....and make sure you use only a YS check valve.

rlipsett

I have replaced the plumbing and looked at the diaphram which appears still good. the ys check valve appears to be working so I will put it back together and see if anything changes. thanks for the ideas

petec

My Feedback: (58)

Check the valve cover gasket too, as if it is not sealing you will lose pressure.

Four Stroker

Remember that the valve cover is the air chamber on the 53/63/70. Any leak that leads to this chamber will give you fits. That includes the valve cover gasket, the O-ring push rod tube seals, and the transfer tube from the carb to the head O-rings. If you fix the tank pressure leak and it still don't run, look at these things. The plunger silicone nipple in the reg. will take a seat/wear in a particular position. If if gets moved around, it will not seal. A new plunger nipple will fix many problems.

If the diaphragm is not the newer white plastic kind, replace it !