1998 Johnson 90hp

[ciscodlr]

Hello everyone, any help is greatly appreciated, I have a 1998 johson 90hp spcl. model J90tslecm, just had new pistons and rings installed by a so called marine mechanic, first day on the water going out to fishing hole about 10min.ride actually did pretty good. But on the way back, hard to start, idle rough, strong smell of gas (no leaks detected) tach wouldn't go over 3000 rpm (full throttle) it was at 5000 on my way to the hole, it actually ran smooth while underway, and when arriving at boat ramp died while idling, I noticed fuel mixture coming out of exhaust ports, now mechanc won't return my calls. Thanks for your time fellow boaters.

 

[trendsetter240]

Re: 1998 Johnson 90hp

Did the "mechanic" explain the proper break in procedure for an engine that has been rebuilt?

Running 50:1 premix along with the VRO for the first 10 hours of use.

Not operating the motor above 3500 RPM for the first hour.

For the next hour only using full throttle to plane then reducing speed to 3/4.

Change engine speed every 15 minutes.

And finally to AVOID continuous full throttle operation for the next 8 hours.

My guess is no since you said you ran it at 5000RPM on the way to your fishing hole.

 

[ciscodlr]

Re: 1998 Johnson 90hp

not a word

 

[bktheking]

Re: 1998 Johnson 90hp

Non DFI Break in:

First 10 hours:

? Double your oil with a major manufacturer TCW-3 Oil.
? Use 92-94 Octane Fuel from a major manufacturer.
? Do not use fuel with alcohol as an additive.
Initial Break-In & Warm Up Procedure
? Allow 4 hours at idle speed only for break-in of new pistons or rings.
? Avoid continuous full throttle operation for the first 10 hours of operation.
? Liquid cooled engines require that the engine be brought gradually to normal operating temperature to avoid cold seizure resulting from pistons expanding faster than the cylinder liner.
RPM Recommendations
? DO NOT RUN ENGINE AT CONSTANT RPM FOR PROLONGED PERIODS OF TIME.
? After gradually bringing engine to normal operating temp., operate engine in gear at approx. 1500 RPM for 20 minutes.
? Operate in gear at no more than 3000 RPM for the next 60 minutes.
? Cruise at 3/4 throttle or less for the next 4 hours.
? Occasionally reduce throttle to idle speed for a cooling period.
? During the final hours of break-in you can operate at full throttle for periods of 2 minutes or less.
? Re-torque the heads after 10 hours of operation. (V6 OMC: 20ft lbs / V6 Merc: 40 ft lbs)
Note:
? Use only enough throttle to plane your vessel and then throttle back to below 3000 RPM.
? Avoid operating in the 3000-4000 RPM range at all times during the 10 hour break-in period.
? During the 6th hour of break-in, plane boat quickly and then throttle back to maintain minimum plane speed.
? During this 6th hour, you can throttle up to 3/4 throttle for 1-2 minutes, then return to minimum planing speed.

 

[trendsetter240]

Re: 1998 Johnson 90hp

not a word

Nice mechanic!

Well, first thing I would do is pull the spark plugs and do a compression check.

Click to the Johnson and Evinrude outboards forum and right at the very top will be "Compression test How-To's?". You will find all the details on what you need to do.

 

[bktheking]

Re: 1998 Johnson 90hp

The rings expanded too much and caused it to start to seize up. Add more oil to it as they say, double it!!! and get it idling in water asap, this is the most crucial time to keep that motor running or it may have already locked up.

 

[bktheking]

Re: 1998 Johnson 90hp

Nice mechanic!

Well, first thing I would do is pull the spark plugs and do a compression check.

Get it idling for a bit with double the mix and then check compression, don't you think?

 

[trendsetter240]

Re: 1998 Johnson 90hp

Get it idling for a bit with double the mix and then check compression, don't you think?

Yeah that's a good plan for sure if it will idle. Mix 50:1 in the gas or 25:1 if you don't have oil injection hooked up.

My first thought was that he already toasted one or more cylinders.

 

[bktheking]

Re: 1998 Johnson 90hp

Ya that's unfortunate, I did a lot of research when I rebuilt my 9.9, they say the most critical time is the first couple hours of life, I ran 20:1 and idled it in the barrel for an hour then ran it part throttle for another 1/2 an hour varying the throttle up and down. Makes a nice oily mess but at least you know it's done before taking it out for the first time.

CISCODLR, I hope to god you can get this thing running after dropping that kind of coin, mechanic man may be in for a visit I have a feeling.

 

[Faztbullet]

Re: 1998 Johnson 90hp

It sound more like a fuel problem flooding a cylinder than a siezure, pull front air cover and see if fuel runs out carb/s when you pump bulb. I didnt see anything about a miss or rpm loss to think you have siezed engine.

 

[bktheking]

Re: 1998 Johnson 90hp

Fazt- wouldn't run past 3000 rpm full throttle on the way back, is that not loss of rpm when he got 5K on the way.

 

[ciscodlr]

Re: 1998 Johnson 90hp

First of all , thanks to everyone for your advice, I finally got a hold of mechanic and he will take a look at it on Monday and hopefully we can come to some type of agreement on repairs, will keep you posted.

 

[Faztbullet]

Re: 1998 Johnson 90hp

Hey Bk .I guess I need to get better glasses as I read that post twice before I saw the 2000 rpm loss:redface:

 

[ondarvr]

Re: 1998 Johnson 90hp

It sort of sounds like it fouled a plug or two.

 

[ciscodlr]

Re: 1998 Johnson 90hp

Hey guys, I decided to rent a compression gauge at a local auto parts store, figured I would check the cylinders, before taking it back to the "mechanic" I removed all plugs and checked them and they all read 100 psi, when most of you guys mentioned the engine seizing up, did you mean like,locked up where it wouldn't turn? 100 psi seems a little low to me.

 

[ciscodlr]

Re: 1998 Johnson 90hp

And by the way ondarvr the two plugs on the same head were fouled (port)

 

[Dhadley]

Re: 1998 Johnson 90hp

A couple of things - 5000 top rpm is lugging that motor, not good. Make sure it has the right Champion plugs. And don't run 92-93 octane.

 

[bktheking]

Re: 1998 Johnson 90hp

100 psi seems low for a rebuilt motor but the rings haven't been broken in yet, did you run it with the doubled amount of oil since you shut it down and at low rpms? I think compression at this point is moot, it won't give you proper readings. I think you need to have a conversation with your "mechanic" to find out exactly what he did to rebuild the motor. As far as seized you said the rpm's dropped, when motors are rebuilt they are either honed or rebored giving the rings a new surface. When the right amount of oil, essentially double as advised isn't used it won't allow the rings to seat properly and causes too much expansion and friction, direct metal on metal contact is occuring. If you can turn it over it isn't seized, but it may have been on it's way to becoming seize, not enough lube and too high an rpm is a recipe for disaster to any motor that is new or rebuilt, and not to mention running it WOT without a chance to break in. The new etec use different tech (Teflon I think) in their cylinder design to allow for WOT out of the box, but they are a totally different beast. A proper break in allows the oil to form a glaze on the cylinder walls and will increase compression over time, right now if rebored or honed you are dealing with a cylinder surface that has hatch marks on it. I just got off the phone with my father who has been a mechanic for 40+ years and rebuilt more engines than i've seen and forgotten more than I'll ever know, his opinion is the motor is as he put it is "f*c*d", I trust his opinion but miracles happen

 

[ciscodlr]

Re: 1998 Johnson 90hp

I haven't ran it at all since I brought it back in from the water, so i haven't used the double amout of oil thats been recommended, to be honest, I am concerned about causing anymore damage. I was intending on talking to the mechanic first. You mentioned talking to the mechanic about what he did to rebuild the motor, what kind of questions would you suggest asking?

 

[bktheking]

Re: 1998 Johnson 90hp

I guess you could start by asking if he broke your motor in for you, seems like it would be a good thing for him to have done without telling you about the "break in" procedure.

Is this guy some craigslist mechanic working at $20/hr or was the a marina with certified marine tech's rebuilding @ $95/hr with warranty.