Buying used 2-02 90 2cyl, questions...

Looking at buying a used 2002 90HP 3cyl 2cycle.

Anything in particular I should look at with this model? I've always had JohnnyRudes, so Mercs are new to me...It's a carbed oil injected model. Are these generally reliable models?

I couldn't find the model/serial # plate, where is it?

When I brought the T&T up and down, it seemed to work fine, but acted differently than the JR's I've had. On the JR's, after after about 3/4 of the way down it hits the "trim" spot, you hear a clunk and it starts moving slower. The Merc didn't do this, it moved at the same speed up and down throughout the entire travel. Is that normal?

Thanks for any comments on this model.

Re: Buying used 2-02 90 2cyl, questions...

It's a single-ram trim system, so even rate motion is normal. It does have a tilt range however. If you go in gear and apply throttle when the motor is tilted high enough (into the tilt range), the thrust will bring the unit down into the trim range. Don't be suprised or think something's wrong when it does that sometime. Three-ram Johnnyrudes do it too.

They're decent enough motors. Not as nice and the Johnnyrude V-4 90's, but still nice. One thing you will notice is rough idling. It's an unfortunate characteristic. They are the roughest idling outboards ever built. They do a little fudging to help that out by adjusting the idle needle on the top carb lean to make it idle on the bottom two. That smooths out the idling, but it makes the motor stumble on acceleration. For best acceleration, it's best to have all three idle needles adjusted to the same 1 1/4 turns out (ballpark adjustment).

Re: Buying used 2-02 90 2cyl, questions...

Agree on the rough idle and too lean a carb causing stumbling outta-da-hole. You'd think a 3 cyl would be smooth as silk, my 70 hp OMC was but it was only 70 hp.

Other thing is that it has a 2.3:1 gearbox and if you are putting it on a light, fast boat, you will be needing a high pitched prop. A high pitched SS prop causes what's known as "clutch dog rattle" which is a clunking noise in the lower unit that occurs at idle in gear and just above. According to Merc it hurts nothing but it makes a lot of noise and makes you think the thing is fixing to blow. A lighter/lower pitched prop doesn't do it.

Other than that it is a sweet running-sounding with plenty of whoopie. Loves to run.

Mark

Re: Buying used 2-02 90 2cyl, questions...

Hey blaster

Not sure if this helps but I have a 1998 oil injected, carbed 60HP Merc triple. It also has a rough idle, and it stumbles a bit getting out of the hole. Other than that, it has been very reliable so far, and I kind of like the sound of it, rumbles like a harley at idle. Mine is a jet, so it has quite a unique (and loud) sound...

Does anybody know if my motor would be similar to the 90HP you are talking about? Mine has a jet on the lower end, and I sure would like it to accelerate a bit faster, and more smootly. I thought it might have been dirty carbs, but I cleaned them, put a new carb kit in, and it still seems rough getting the boat up on plane. You think a carb adjustment might help this?

Re: Buying used 2-02 90 2cyl, questions...

Engines are close but yours is a 52 cu in and the 90 is an 85. I'd expect yours to idle much smoother than the 90 if my large diameter piston theory is correct....just a theory.

Might try a decarb first then might open the jets 1/4 turn. My 90 acted like that too, especially first thing in the morning.

Mark

Re: Buying used 2-02 90 2cyl, questions...

I'm a little confused by the rough idle issue on 90 HP triples. My 75 is quite smooth at idle, but then I run non-surface gap plugs. Idle timing is the same on both motors although the 90 runs 2 degrees more at WOT. If porting is different, that would possibly account for the possiblity of rough idle, but I have owned both J/E and Merc triples and found both to be about the same. Not objectionable by any means. As for out of the hole bog, I've found that a gradual, but still rather quick increase in throttle rather than a sudden stab results in zero bog and idle mixture must be finely tweaked.

Re: Buying used 2-02 90 2cyl, questions...

My boat is used as a riverboat, and I need to be able to jump up on plane very quickly, to be able to get out of tight pools, on occasion. The way that my 60HP (Jet45) presently gets up and goes is not objectionable, but it seems to me that it could be faster, and smoother. I use the throttle as Silvertip describes, and while the motor accelerates smoothly through the lower RPMs, it kind of jumps suddenly in RPMs, near WOT. Almost seems as if it may be something slightly blocked in a carb, as it almost 'switches' to full power, near WOT. Not sure if this makes sense, but it is not the smooth transition through RPMs that I'd expect. Is this normal for this motor (1998 3cyl 60 Merc)

This was present even after I cleaned and rebuilt the carbs last year, and I am thinking some varnish might have come through the fuel line, or somewhere. OR, maybe it is worth opening the carb jets 1/4 or so...

otherwise, the motor runs like a top, and as was mentioned, it LOVES to run!

Re: Buying used 2002 90 2cyl, questions...

Re: Buying used 2002 90 2cyl, questions...

Just an update...We bought it!

Turns out it's really a 2003 according to the model plate on the motor, not a 2002.

We took it out on the lake and she seemed to run just fine. Idling wasn't quite as bad I thought it would be from reading the posts, so that was a bonus. There was a bit of a stutter from low to high RPM, but once it was past that, it was fine. It's going on it's 5th season, so maybe carbs need to be taken out and hosed down?

It was running on it's original plugs and last season's gas, so that might be part of it too.

I pulled the plugs and did a compression check. The top cylinder was 120 and the bottom 2 were around 118. It was doing 5200 RPMs trimmed all the way up and doing just over 40MPH into the wind, with 4 adults on a 17.5' 1500 pound V-Hull.

Is 5200 RPM in the right range?

Thanks again for the responses!

Re: Buying used 2-02 90 2cyl, questions...

It would be better if you saw 5500 but 5200 is in the middle of the WOT range.

Re: Buying used 2-02 90 2cyl, questions...

To clarify my "rough Idle". I'm coming off an I6 direct charged tower to a loop charged 3 cyl. Nuf said? I got spoiled.

You can probably clean up your mid range stutter with Sea Foam cleanup (decarb) and keeping it in the tank. Trying to remember but I think I did that to mine.

And I am running the same regular plugs Silvertip is and they do improve performance and starting.

I think you are in the right rpm range. 4 adults is not what I call a light load so when you get out by yourself you should be around the upper limit (give or take). I'd leave the setup alone for now.

But the question is, what is your normal load? If 4 adults is and you want to bump em up to 5500 then you could play with your setup (raise the engine a notch or two) or get a 1" lower pitched prop of the same make/type as you are running.

The engine weighs 300# so if raising is your answer get an engine hoist and hang it from the flywheel nut with an adapter....or if you have several friends (to stabilize the engine) you could use your trailer tongue jack with the skeg on the floor.

Mark