break-in motor

[TruthWalleyes]

two years I blew up my 40hp tiller motor.

got the call today that it is done being repaired.

new pistons and bored cylinders.

ill need to break this 2 stroke in like new.

how do i go about doing that?

thanks.

[CAMAN]

I'd take the advice of the guy doing the work, as he is the one that is most likely warranting it.

[TruthWalleyes]

just a small motor mechanic who doesnt do much boat motor work. no warrenty. he advised that i break it in like a new motor. not sure what the do's and dont's are with a newly repaired motor.

[Macgyver55]

Do you know what caused the break down? Was it a lean condition, an oiling problem, overheat or a failure of a part? Its vital to make sure the cause was found and corrected before running it at all. Dirty carbs will cause a lean condition and score pistons and cylinders, and older Evinrude and Johnson motors had the VRO problem and any motor is vulnerable to water pump failure. Any of these that are not corrected will put you right back where you started.

Aside from that, I normally recommend (even with oil injection) to add a pint or so of oil to your gas on the first tank. Avoid wide open throttle starts for the first couple tanks, vary your RPMs and dont cruise at a steady speed for long periods. Once you get through a couple tanks and several heat cycles you should be fine just running it how ever you normally would.

[Superduty]

Most new outboards have a double oiling period and you need to vary the RPM frequently. Do not run a long time at any one RPM. You also won't be able to run WOT for the first hour or so.

[TruthWalleyes]

It was a lean condition which lead to detonation. This happened (I believe) Because i'm an silly-me and added way too much seafoam to my gas and the first time on the water in the spring i got terrible knock. So it is my belief that the lack of octane caused the failure. The mechanic and I took it apart back when this happened and couldn't find anything else that would cause a lean condition...So i believe it was the fuel, seafoam lowing the octane. At the time i didn't want to spend the $1,000 to fix and bought a 25hp from a friend for a great deal. This spring i decided it's time for the 40hp to see the water again.

This is a mid 80's evinrude. What is the VRO problem? Failing fuel pump?

By a "Double Oiling Period" do you mean double the ratio of fuel/oil for a certain period of time?

[Superduty]

By a "Double Oiling Period" do you mean double the ratio of fuel/oil for a certain period of time?

If it's 50:1 like most outboard you should mix it at 25:1. Basically, add twice as much oil as you normally would run.

[CaptainMusky]

The VRO issue was an oil injection problem. Many guys would disable it and just mix the gas. It was quite commonplace. I had a mid 90's evinrude and never had the problem, but I think there were about as many with the problem as there were without it.

Regarding breakin, just add extra oil in the tank. If you have an inboard mounted tank (like 20 gallon or so) running low rpms while varying speed for the first 10 hrs.

If you have the smaller portable tanks go through a tank of fuel at lower speeds, then the second tank you should be good with some WOT runs.

Some guys say break it in like you plan to use it, others say take it easy. I have always done the take it easy approach and never had issues with any 2 stroke.

That seems a bit odd that Seafoam could have done that. I wouldnt think it would reduce the octane that much. You may have had a bunch of water in the gas or something. Gas is so crappy these days and it seems everything has ethanol in it which is an enemy to 2 stroke motors.

[gunner55]

Variable Ratio Oil pump on 93-96(?) Evinrude & Johnson that was total junk.

[Gus]

If it's 50:1 like most outboard you should mix it at 25:1. Basically, add twice as much oil as you normally would run.

Also vary your RPM's. Don't go full bore out across the lake holding her to the max. Change RPM's often. Up and Down.

That's what our repair guy suggested after rebuild.

That and don't loan your boat to someone with no clue... (drove it into a sandbar sucking up sand and destroying the impeller then continued on like nothing happened until she overheated.)

[TruthWalleyes]

Thanks for the help guys.

This is not oil injected so no VRO problems.

6 gallon fuel tank on board.

That seems a bit odd that Seafoam could have done that. I wouldnt think it would reduce the octane that much. You may have had a bunch of water in the gas or something. Gas is so crappy these days and it seems everything has ethanol in it which is an enemy to 2 stroke motors.

Don't know what i was thinking at the time, but for whatever reason i had added 2 cans of seafoam to 5 gallons of gas Just a tad more than recommended LOL. So I am the most likely culpret to the detonation.

I'll take it easy for 10 hours varying rpm's with light usage in and out of full throttle. I'll probably just take a nice long trip or two up and down the minnesota river once i get the truck fixed.

Good advice guys. thanks a bunch.

[PerchJerker]

The instructions I was given for my DFI motor were to vary the throttle frequently for the first hour and to not go above 4000 rpms in the first hour ..... for the 2nd hour to vary the throttle frequently and to run WOT every so often but only for a few seconds at a time ...... and for hours 3-10 to not run at WOT for any extended periods of time.

The instructions I was given for my 4 stroke kicker were to vary the throttle frequently but run at WOT sooner and more frequently and for slightly longer periods, to make sure to seat the rings so the fuel couldn't get past them and "make oil".