Breaking in new Yamaha 90 -- anything I should be aware of?

T

Tortuga

New member
Tortuga now has her new Yamaha 90 EFI mounted and ready to go. Tomorrow I'll put her in the water for a ride. The manual gives a break-in regime that is pretty basic:

1st hour -- run engine at 2000 rpm
2nd hour -- run engine at 3000 rpm
Next 8 hours -- run engine at any speed but avoid opearting at full throttle for more than 5 minutes at a time.
After the first 10 hours -- operate engine normally

My dealer gave a somewhat different regime: For first 20 hours, avoid running past half throttle. He also said that full power won't come in until about 50 hours -- and if I run at WOT before 20 hours I can limit the engine's full power by 15-20%.

So, at the risk of overthinking this, should I just run according to the Yamaha manual -- possibly with the additional extra of avoiding WOT beyond 5 minutes until after the 20 hour service?

Thanks for any suggestions. Oh yea... I'll be running a 13.5 x 15 AL prop.

Matt
 
Tortuga":1coo8y5s said:
Tortuga now has her new Yamaha 90 EFI mounted and ready to go. Tomorrow I'll put her in the water for a ride. The manual gives a break-in regime that is pretty basic:

1st hour -- run engine at 2000 rpm (Max rpm, vary speed as needed)
2nd hour -- run engine at 3000 rpm (max rpm, vary speed as needed)
Next 8 hours -- run engine at any speed but avoid opearting at full throttle for more than 5 minutes at a time. (Make yourself a table, adding 500 rpm per hour to the max allowed, to the max the engine will go, avoiding long periods at max rpm)
After the first 10 hours -- operate engine normally ( Just avoid running max or near max levels for long periods)The goal is to start the engine off at low rpm and allow the parts to wear in and smooth out the rough machined surfaces, gradually increasing the rpm levels to seat and fit everything nicely. The rings/cylinders will only finally seat at max rpm, but too much too soon, will cause problems, hence the precaution to not run at wide open throttle at first or for long periods until the rings are properly seated. Varying the rpms within the schedule is actually helpful.

Just follow the general guidelines, vary the speeds, and avoid highr rpms at first, according to the schedule.

My dealer gave a somewhat different regime: For first 20 hours, avoid running past half throttle. He also said that full power won't come in until about 50 hours -- and if I run at WOT before 20 hours I can limit the engine's full power by 15-20%. Sounds simple, but overly precautious to me. You need some high rpm short sessions to seat the rings. One problem they have with the F115, which has hardened rings and other parts, but is the same basic engine, is not getting the rings properly seated because of too low initial operating rpm, which makes the gas/air mix leak behind the pistons, and dilutes the oil, increasing it's volume, known as "making oil".

So, at the risk of overthinking this, should I just run according to the Yamaha manual -- possibly with the additional extra of avoiding WOT beyond 5 minutes until after the 20 hour service? That would be a good approach, basically.

Thanks for any suggestions. Oh yea... I'll be running a 13.5 x 15 AL prop. Good initial choice, let us know what your wot rpms are after 20-30 hours.

Matt
Click to expand...

Best advice I have / my $0.02!

Joe. :teeth :thup
 
I'm breaking in a new Yamaha 75 EFI on my 19 and the manual is the same as yours. My dealer told me basically to follow the manual with varying rpms and go to wot for a few minutes every once in a while for 3-4 minutes. I think your dealer is being overly cautious and when in doubt I always follow the manufacturer because I bet :lol: there is a chip in that thing showing your history. This will be handy if you need any warranty work that you followed recomended procedures. You'll also hear from some dealers to just run them wide open right off the bat. That may not be so good. Have fun with that engine it's a beauty. :o
 
ghone wrote:

" I bet there is a chip in that thing showing your history."


*******************

Wait until you see the printout from the dealer's computer!


*******************

:note "Santa knows whether you've been good or bad" :note

:note "So be good for goodness sake":note

:xlol :xlol :xlol

Joe.
 
Thanks to everyone for the suggestions! I ran the boat today for an hour -- varying RPM up to 2000. A couple of things I noticed -- first, when putting the boat into gear (both forward and reverse) I heard and felt the gears engage with a much more apparent clickety click and thump (this was at low idle). I am assuming this is a function of the lower unit not yet broken in and am hoping that this will diminish over time.

I also noticed that my speed was lower at mid RPM with the new engine and prop than with the Yami 70 2 stroke. But, this is probably just a function of the gear ratio on the new motor and once broken in I can test different props. Obviously I haven't yet tried WOT.

I'll get to run the boat again on Monday. So far so good! Great starting -- much better charging than the old motor. Quieter (of course) and absolutely smoke free. How is that possible!
 
Tortuga":2sdv72n8 said:
Thanks to everyone for the suggestions! I ran the boat today for an hour -- varying RPM up to 2000. A couple of things I noticed -- first, when putting the boat into gear (both forward and reverse) I heard and felt the gears engage with a much more apparent clickety click and thump (this was at low idle). I am assuming this is a function of the lower unit not yet broken in and am hoping that this will diminish over time.
Click to expand...

The clickety click and thump may be the result of you "easing" the engine into gear. On my H90, it will make a lot of extra noise if I don't move it quickly into gear. I try to be a little more assertive on the throttle/shift.

Steve
 
Jut a note:

When you shift an outboard, don't try to go into gear slowly, that just makes the shift dogs (clutch) clatter for a longer period of time.

Wait for the engine to drop to idle rpm, then shift crisply and the shift dogs will quickly engage and lock up without clattering over each other for a long period.

There's no friction clutch in an outboard. The shift dogs are mechanical and look like this:

912607new.jpg


The internal splines are for the drive shaft, and the squarish projections are the dogs that fit into a receiving member cut out for them. Shifting slowly just grinds off their corners. A quick shift at low rpm and low torque/load engages them quickly without clanking their corners off excessively.

Shifting may seem smoother after some of the square corners have worn down a bit somewhat, however.

Joe. :teeth :thup
 
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