How difficult are Carbs?

[Cucumber]

Hello. New Member here from S.W. Florida.

2001 Johnson 90 PLSIG.

I purchased the boat last year and ran it all summer and fall with no problems.

Last trip of 2014 the motor would stumble at WOT. It happened a few times over the summer but would clear up as the day went on. This time motor continued to run rough..

Inspected for fuel leaks and found fuel coming from the Vapor Separator. Purchased new gasket and no more leaks.

Next time out on the water, the motor was still stumbling at wot and began stumbling/hesitating on takeoff at low rpms as well.

Limped in and called it a day.

I took covers off of motor and found that the lower starboard carburetor was leaking fuel from the bowl. The brass drain plug was loose and stripped. The other three were tight.

I'm also having a lot of unburned oil/sludge leaking from the prop. This and the plugs have me thinking I am running too rich. VRO is disconnected and I premix. 50/1

Motor starts very easily and idles great.
Questions:
1: Are the carbs very difficult to overhaul? I've watched videos and seems pretty straightforward.
2: Rebuild all carbs or just the one?
3:Are the carb rebuild kits all I will need to order or will I need jets and orifices that don't come with the kit? I assume I will need a new bowl for the stripped screw on the one carb.
4: How difficult is the sync once the carbs are re-installed?
5: Is this a good time to do the water pump as well since the carbs will be removed and access is easier to shift shaft.

The motor is pumping water fine but it has been a few years since the LU has been dropped and I would like to grease the shaft and have some confidence for the future.


I have done a couple water pumps on Suzukis in the past and feel I could do the pump. The carbs have me a little intimidated. Mainly the sync.

I was quoted about a grand for the two services and I would like to learn my motor as it is in good shape for it's age and I plan to keep it for a while.

Sorry about the wall of text and all the questions.

Any help would be greatly appreciated.

Thanks in advance.

 

[leaky]

Do you have a repair manual? I strongly suggest buying one, both to do the work and to decide which jobs you want to do.

These are both very reasonable things for someone to do on their own, with the water pump being the simplest.

I'm not sure if there is even a mixture adjustment on that engine - if there isn't it's usually real easy. The sync part (assuming you mean top/bottom carb sync not mixture) is not something normally you do not need to adjust when doing carbs, you leave the link/sync adjustments as they are unless you intend to do that part of a tune-up.

If there is a mixture adjustment it's not very hard to do just takes a safe piece of water or a test tank, once you have it running reasonably well you pull the plugs after 10 hours or so and make small adjustments to make it even across the cylinders. It's good to check the position of any mixture screws prior to disassembly, ie turn them in until they gently seat while counting the turns.

I think you mean PLSID - if that's the case the bowl is available at a modest cost (like 35 bucks) and that will fix your stripped plug too.

You always rebuild all the carbs at once. Get the kits that have the floats in them. Yes it is a little easier to undo the shift shaft with the carbs off. The gunk coming out of the engine, who knows - yes if you have a leak it will be worse but anything with a carb tends to do that.

Jon

 

[leaky]

Oh and on the water pump - many do it every year, some engines you need to, most you do not, but at least every few years is a very good idea. Same deal - get the kit with the impeller and body. It's also good to take the lower unit off fairly regularly so as to prevent anything from seizing, helps keep the splines on the crank from rotting away too.

Jon

 

[leaky]

Haha - ya what he said.

One thing to add regarding the ethanol, as that triggered a thought - if you are seeing evidence of fuel lines deteriorating when doing the carbs replace the lines. If nothing has been done since 2001 you are in the ballpark for those headaches and the lines may just totally screw your perfectly clean carbs up again.

 

[Cucumber]

I need to find a genuine Johnson repair manual. The seloc is not so good for my specific engine.

It is indeed a PLSIG. It does not show up anywhere. From the research I've done the G in PLSIG must stand for Graphite Paint.

I don't believe the Carburetors have any adjustment screws.

I have located the bowl, part #433000. Would it be possible to just replace the leaking bowl and then if engine is still running rough then do the full carb job.

Honestly, I was thinking of just epoxying the bowl closed and then running the boat and see if the problem is isolated to the one carb. I don't have a problem having all the carbs done if needed, but the problem may be just this one leaking carb bowl.

No problems with water pump currently. Just being proactive.

I was quoted $1000 for both jobs which I will gladly pay if required. I just thought it could possibly be the one leaking carb and it couldn't hurt to try plugging it up(since it will eventually be replaced) before going ahead with the full rebuild.

I also uploaded a photo of the J90PLSIG plate on the motor.

The J90PLSIG doesn't show up on any part sites and I have been ordering parts off the PLSID. Like I said, my only guess is Graphite Paint, going by the Evinrude/Johnson Identifier. I also saw the earlier years a "G" stood for "Special Styling".

Here is a pic of the motor.

 

[leaky]

If you are gonna mess with the carbs just do them right - I mentioned the bowl because you said the threads were stripped.

The best way to blow up a 2-stroke is to run it for awhile with a carb problem.

Jon

 

[daselbee]

PM sent.

Oh, and yes, the carb system does have adjustable needles.

 

[Cucumber]

Disassembled the carb. Put a new bowl on it. High speed orifice that had to be switched out to the new bowl was super clean. NO build up whatsoever in old bowl or passages. Float and pin seat nicely. Reassembled with new gaskets.

Will water test in the next couple of days. New bowl now is sealed. No more stripped screw.


old bowljust discolored, no build up.