Need help with 90hp evinrude

[Pappy]

You are having your share of issues!
There are only three usual ways to shear a key. Running in a resonance RPM range which I am guessing you are not. Not cleaning the tapers prior to placing the flywheel back on the crank (most likely culprit), or not torquing the flywheel. If either of the last two was the reason then a piston stick/rapid decel can create a key shear. Not normal or likely but it can. Lets hope it was just a key.
Now, unless you engine was far enough out of time to kick back against the starter the lock-up may be a concern.
Compression drop you found may have been the key to it.
On a light piston stick the engine cannot be turned over by the starter immediately after the stick. After a couple to a few minutes the piston cools enough to free itself from the cylinder wall and the starter can do its job better. After idling and slow running that area that stuck kind of "heals" itself to a degree and compression numbers can come back up a little.
Unless you feel like pulling that cylinder head and looking in there or pulling the intake by-pass cover and looking in there then just be aware that it may have stuck and you will need to run extra oil for a while and run easy to flush debris that will be coming off the walls and piston.
If it stuck a ring with debris it will shorten the service life of that piston/cylinder. Not trying to scare you...just educate you.
Now, let me get this straight, you still have not physically pulled the HS jets? Without pulling them and cleaning them there is absolutely no way you can tell me or fool yourself into absolutely knowing they are clean. I would rather see your engine running with a completely closed off HS jet than one that is still just dirty enough to create a lean condition. And that run may have stuck the piston. Hello?
The plug color will not change fast enough on a single WOT run to let you know the condition.
Do your part the right way and quit taking short cuts. If not then my help is done.

 

[Fordracing2105]

Yes I did pull the hs jets I said in an earlier post that I did that. I'm sorry I didn't word it right. Not sure what short cuts I took. And yes it was my fault that the key sheared I never tighten nut nut the last time I had the flywheel off from doing the timer. Sounds like you already had enough. And the boat ran great right before key sheared and I thank you for your help.

 

[Pappy]

Not that I have had enough by any means.
Through the years I have offered a lot of help to a lot of folks on this stuff. Most of the time it was done according to plan. Sometimes short cuts were made and problems persisted. Other times different folks would say to do something else . At these points I have learned just to step back and let things happen. Or, as in the case on these forums, sometimes bad advice can cost a person money and I will offer information with back up and try to get it back on track.
As long as you want to get it right and do things the right way I still enjoy trying to teach and help.

 

[Fordracing2105]

Your help is greatly appreciated from me and others. And I understand not everyone listens to what or how there told to go about something. So what short cuts did I take from your advice. I had practical everything off of this engine at least 5 times things have been check double check Replaced swapped out test and I forgot to torque the flywheel because I figured it would have to come off again. All I was doing each time was hitting with an impact quick. I wouldn't really call that taking any short cuts.

 

[Pappy]

Short cuts.
I guess since others are reading this and hopefully learning from it this would be a good chance to go over what a "carb cleaning" is.
As I said earlier....much rather see an engine run on a totally blocked off jet than one that is only partially blocked. Your short cut was
before the help started so no short cuts while the help was available to you. Your short cut was to not remove the jets but to just stick something through them and cross your fingers. With mistakes comes knowledge and experience!
When a carb is disassembled (OMC for reference) all jets should be removed and chemically cleaned. Also a good chance to take a number drill and check the jet size.
Orifices and passageways behind jets should also be cleaned and verified by either air, pressurized chemical (tough on the eyes...) or a strand of wire. If not sure....re-clean. Calibration pocket plugs (those aluminum plugs) that reside on the tops of carbs should always be removed and each calibration hole should be verified. Try not to stick anything into them. Brass lift tubes that go down into the fuel column in the bowl and supply fuel to the idle circuit should be cleaned and verified by one of the above methods. Anything that fuel or air flows through should be cleaned and checked. Sometimes a can of cleaner will not do the job.
Parts should be visually cleaned and verified prior to assembly. OEM kits will always include ALL parts necessary for a proper rebuild vs aftermarket kits. Try to stay with OEM.
Why the tirade? Because when you are dealing with a 2-stroke anything other than a full and verified cleaning can result in a lean condition that can destroy a powerhead or at least a cylinder. Clean 80% of a high speed jet and what do you have? A recipe for disaster.
So....when you (anyone reading this) say you have cleaned your carb.........have you really? If you take the time to read through tons of posts here you will see that all too often carbs that have been cleaned have to be re-visited a second and possibly a third time to get it right.

 

[Fordracing2105]

Well I just I can add to this to help others. When I rebuilt my carbs before I got help from Pappy. I soaked than poked shot carb cleaner through every hole I could find. I could physically see light through my hs jets. But there is kind of a void behind those jets on my carbs where crap was built up and I assume fell and blocked later on.

 

[Triple obsession]

An ultrasonic cleaner can be a mans best friend when cleaning carbs.