Problem with 250 pro xs starting and running

[largecar91]

I have a 2008 Mercury 250 pro xs. 450 hrs. Never had any problems with. Couple weeks ago it started acting like it was not getting enough fuel. Slow out of the hole and down about 700 rpms on top.. it shows no codes on .my Rinda. When cranking air pressure is 95 and fuel is 42. When running air still at 95 but fuel is 110. I rebuilt pulse pump and replaced both electric pumps. The high pump didn't work so i put old one back on. Using a shot of ether it will fire up but runs rough. I also replaced spark plugs and it has strong spark on sparky. Compression is 120 all cylinders. Any thoughts on what could be causing this. Thanks

[largecar91]

I checked the Tracker valve diaphragm last night and it is in good shape. Anyone have any ideas?

[pcrussell50]

If you’re confident you’ve addressed fuel, then there is spark… You’re getting spark, but is it advancing like it should? If you properly address fuel and spark then you’re down to brass tacks… Compression and leak down.

-Peter

[XstreamVking]

Replace all the rubber fuel rail parts if old originals. Tracker, fuel dia, air dia. My 225 opti was running ruff at idle speeds. replaced a perfect looking tracker valve ( old green color) it is now running great.
Purple is the new color.

[largecar91]

Replace all the rubber fuel rail parts if old originals. Tracker, fuel dia, air dia. My 225 opti was running ruff at idle speeds. replaced a perfect looking tracker valve ( old green color) it is now running great.
Purple is the new color.. I will probably go that route. Mine are green. Should the fuel pressure be 110 cranking?. It is 110 running but not cranking

[XstreamVking]

I would guess that at "key on" you should have full pressure.

[largecar91]

That's my thoughts as well. I'm still pretty sure it is a fuel issue. Not sure why I am only getting 42lbs cranking and it goes to 110 fuel pressure when running. The pumps are 12 volt electric. They should produce the same pressure running or not. I am going to order another new high pressure pump(returning the one that didn't work) and all 3 new diaphragms.