2002 Newly Rebuilt Yamaha 90hp 2stroke

Can anyone tell me if I should be running twice the normal amount of 2 stroke oil during the break in period of this motor?

Does anyone have the Yamaha recommended procedure for breaking in a fresh rebuild 90hp 2stroke.

I will be running premix from here on out as I deleted the onboard oiler.

I really don't want to mess this up!

Since premixing oil you shouldn't need to double oil.
Break in
Hour 1 700-1500
next 6 hrs don't run over 3000
Next 3 hrs you can run WOT for 1-2 min
Avoid running 3000-4000 as constant speed

I’ve heard not to delete the oil injection on the Yamahas because the carburetor is NOT calibrated for premix because the oil is injected after the carburetor. So the carburetor itself sees gas only, no premix. Also, it’s said not to delete it because the Yamaha system is extremely reliable. Anyone know anything about this, I might be rebuilding one here in about a month and this would be good info. Thanks.

I find this hard to believe as the owner’s manual has you pre-mix the fuel for the initial 10 hour break in period. If the carbs couldn’t handle the pre-mixed fuel, I doubt Yamaha would insist you do exactly that while you were breaking in their engines.

The guys that did the rebuild says they regularly remove the self oiling systems on the Yamaha 2 strokes and none of them have issues with their carbs.

I have been working on yamahas for over 20 years and have never disconnected oiling systems on yamahas ( and for that matter mercs also ) it is a veery reliable system and has warning systems incorporated that will warn of a failure if there is one.. I do not recommend double oil for an engine break in because the over oiling will prevent engine from breaking in i.e. rings and bearings from seating and forming their own war pattern a little extra oil is ok but the main thing is to not make the rngine work hard. lite loads , and no over propping you just want to let the engine run

Agreed. I’ve never understood the double oiling because you actually want the cylinder wall to wear a little(break in). I’ve rebuilt 4 of my own outboards, and broke them in with 50:1 gas and they all turned out great. Several ways to skin a cat though I suppose.