4 Stroke Break-in

I just picked up my new F30 Yamaha yesterday and was coached by the lead tech at the dealership who just got back from tech school. He heard the same message from the Yamaha, Suzuki, Mercury factory people teaching the school, and that message was to ignore what the book tells us on how to break in the engine (first hour 2000 rpm, 2-10 hours up to 3000 rpm, etc etc). He says the factory wants us to warm up the engine, and run it at Wide Open Throttle, with a load in the boat, from the beginning. This prevents ring/cylinder glazing which is what happens by pussy footing the break-in like the book says. He told me to back off every 10 or so minutes, test the water temp at the tell-tale stream, let it cool off at bit, then hammer it some more. He says I will get years more life from the motor and there will be no “oil making” happening from gasoline seeping past the rings and getting into the crankcase. The local dealer told me “all” 4 strokes “make” oil,,,and this must be why. So, if you guys see a F30 on a green Lund Rebel running around pool 4 , it will likely be me, breaking in the motor.

If anybody knows different than this, please post here.

I didn’t “pussy foot” with my break in either, what they dont want you doing is running it wide open for long periods of time, changing the rpms after a few minutes is ideal, if you read my other post about water in my oil, on the bigger four strokes in cold water when trolling alot the engine runs so efficient it dosent ever really warm up, somehow this must allow condensation to build up??? so from now on before I troll in spring or fall I’ll be hammering up or down the river to get the juices flowing in my motor, I just wish someone would have told me about this first. Oh well live and learn, good luck with your break in and enjoy your motor!!

LundgEYE is this the same type of break in on smaller moters 15 and smaller?

I don’t know the answer to that Gillman but I will be talking to the dealer this week and will ask that question of the tech. I do know that if I was to re-break in my T8 I’d go hammer it right out of the chute rather than what I did which was to baby it. I tried to do as the book said but apparently that isn’t a great idea on these high performance, precision built engines.

I broke in a new 90 horse two stroke Merc last summer. Spent a couple of hours running it at various speeds between full throttle and a fast trolling speed. Everything seems o.k.
How do you know if you do it wrong?

Steve, the problem the 4 strokes are seeing will cannot happen with your 2 stroke, that is the oil in the crankcase building up fuller and fuller due to gas getting into it via glazed cylinder walls and rings. Other than that, I am not sure how important all the procedures are with today’s modern machining equipment, and tolerance control. Bearings most likely don’t need the TLC they once did because they are now so precision made. If any marine techs read this, please feel free to jump in and tell us your thoughts.

I’d like to know if there is a recommended air-and-or surface water temps before doing the break in?