Yamaha 90 low power question

[AquaGary]

I have 1987 Yamaha 2 stroke 90, on a 1988 24" sun tracker party barge that i have totally restored.. the boat is currently in storage. I ran into an issue late in the season.with this outboard. I put this engine on at the beginning of the season and it ran great. Then the issue started the engine will start and Idle fine I have very long no wake about 20 minutes.
after I get to the open water and apply full throttle. the boat picks up fine for about 2 minutes and then loses power. this is so bad that I barely made it back to the dock. I'm an avid boater , using our boats every weekend.

1) the water pump seems fine the engine is peeing a very solid stream. and does not feel hot to the touch.
2) I replace the spark plugs I thought may be a fouled plugs and same issue.
3) replaced the fuel line bulb and filter. same issue.
4) check the fuel for water contamination, no water. and seems clean.

In the spring I plan on running a compression check, clean the carbs and may be replacing the fuel pump.

I have a couple of questions:
I read that that this engine, has limp mode for the low oil in the injection tank. ( I think this may be what's happening) I don't have a light for it , but it is full of oil. .
1) can the limp mode be disable? I would prefer to run premix anyway since the oil tank access is difficult
2) is this possibly ignition system problem.? I don't know much about how they work.
3) fuel pump may be?

I hoping some one here who has more experience with these outboards may have an idea on what this issue is?
I know much more about i/os my Chevy powered Chris craft is always very reliable.
I've had good luck with my mariner 40 that was on the pontoon boat (which was also a Yamaha) That's why I bought this 90.
I have order the service manual for this engine

Any thoughts you guys may have

thanks in advance

Gary

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[racerone]

Does spark jump a gap of at least 3/8" or more , yes or no ?

 

[robert graham]

If it runs strong for 2 minutes then cuts out maybe a fuel venting issue...is the vent on the tank open?....

 

[AquaGary]

not sure on spark jump if it is than 3/8 "
I'll have to check the vent on the fuel tank,internal tank, I think it vents on the fill tube, not much there to be blocked

 

[AquaGary]

Found out what was causing this issue. 3 Saturdays ago in the pouring rain , I replace the fuel pump cleaned the carbs and replaced the plugs ran the boat for 30 minutes on the trailer sounded good no issue. . last Saturday the rain finally stopped in ohio. The motor fired right up backed off the trailer go about 200 yds down the lake and it locked up solid. Got a friend to tow it back to the dock. pulled the plugs couldn't turn it over by hand, spun the prop and it seemed tight , checked the oil and not a drop of gear oil in the lower unit. I have never seen a lower unit completely dry. I was so concerned with getting it running correctly I never checked the oil in the lower unit, something I change every year as normal maintenance. I was going to rebuild the unit but after reviewing all the special tools needed for the bearing clearances. and I couldn't find the gears for 1987 yamaha 90 hp. I started looking for another lower unit on craigslist. I came across a 2003 90hp 4cly 4 stroke in cleveland. motor was blown up. Looking at pictures searching crowley marine and comparing part numbers between the two engines. I realized it was about the same and worth a trip to cleveland ( about 250 miles for me one way). I had change the drive shaft and water pump (getting the 2003 apart was a real challenge. motor must have some of it life in salt water) Drove up on Tuesday , took the lower unit of the 2003 and compared it to mine. decided it was close enough , had it bolted on by Thursday and in the water on Friday. Motor ran great all weekend. I know this is a long story but don't be a idiot like me and forget to check the gear oil