Yamaha 15hp 2 stroke won't plane

2009 model.

She just won't get on plane. I had a certified Yamaha mechanic look at it for an idle condition and since then I have this problem. Unfortunately we're not in the same area as the mechanic anymore. This is what's been done:

-Carb pulled and cleaned. Has always been very clean.
-new plugs.
-new primer bulb.
-Prop checks out ok.
-butterfly valve shaft turns when linkage engaged and engine in gear but not running.
-rpms come up in neutral.
-pumped primer bulb when trying to plane.
-compression 119 on both cylinders.
-gas is 50:1. reg pump gas. Same as usual.

What am I missing? We live on our boat and this is our car to get to shore. we are getting desperate. Help!

Thanks for any info you can provide.

I would say it is running on 1 cylinder ----Check for strong spark.----Yes the RPM come up in neutral.-----Means nothing.----It will rev up on 1 cylinder.-----Check flywheel key too.-----When was a new water pump impeller installed ?----Needs one every 5 years.

New water pump impeller installed 8 months ago, pees good. To test the one cylinder theory just unplug one and see if it makes any difference?
How do I check flywhell key?
Thank you!!

Just diagnosed a failed fuel pump diaphragm.

Do you use ethanol?