1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

[cc190cc]

Greetings,

I have a 96 Merucy 90HP 2 stroke (90ELPTO). Serial number - 0G405715 - I purchased this boat last year, always idled pretty rough. Higher RPM it seems to run well, mild hesitation coming up on plane. Smokes quite a bit after idling for 10 - 15 min, like if im trolling.

I have been trying to figure out how to adjust carbs and getting familiar with the engine. I noticed today on the three carbs, the bowl vent jet screw is missing, take a look at the pic. I know this is a vent but could it be venting to much??? does this matter or should i get the vent screws for it??

Can anyone tell me briefly how to adjust the carbs on this, again, idles bucks pretty rough, mild hesitation probably around 2000 rpms, screams at high RPMS (runs well).

Does anyone know where i can download a factory manual for this, something that may tell me exactly how to adjust carbs, unless someone can help.

I feel like i can do whatever labor is necessary, very tech savy, i just cant afford to pay marina right now to go through engine. Im sure it would be a min. of $500 bucks.

Chad

 

[saumon]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Here's the shop manual

http://rapidshare.com/files/213240343/75-90-100-115-125.rar

password to extract each file is "ribforum"

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

awesome thanks, i think i can figure it out with this manual. Any other feedback from you guys would be great.

Chad

 

[lineman22]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

I have never gotten to the download. Tried every time I see one listed. How hard can it be?

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

go to that link, you have to click like download now, wait like 40 sec for download to begin, save it, it saves as a zip file so you have to unzip it. It is incredible the amount of information in the manual. I am going to check compression, timing and carb adjustments tomorow.

My engine was smoking quite a bit and i actually just used the manual to adjust the oil mix linkage to where it is supposed to be. It was definately out of adjustment so hopefully that will help w/smoking.

Chad

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Just did a compression test on it, 100 110 100, is it safe to say this motor is smoked.

Chad

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Those look like WME carbs. I'm pretty sure that's the way it's supposed to be. Try fatening up the idle screw 1/4 turn. Sounds almost like its lean or maybe getting too much oil.

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

they are WME's , do you guys think i should look for a new motor or try to rebuild. Or just run it??? 100PSI is way low!

Chad

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

they are WME's , do you guys think i should look for a new motor or try to rebuild. Or just run it??? 100PSI is way low!

Chad

These are easy to rebuild and good motors. You can rebuild it for a fraction of the cost of a new motor. You might have problems finding someone to bore it locally if it needs it. Sending it out would slow you down a little and this is the busy time of the year so parts are at a premium. If you think you can make it last the rest of this season I'd go that route and then rebuild it in the off season.

 

[saumon]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

How do you check compression? Try it like this: warm the engine for a few min then stop it, remove all spark plugs, flip the kill swith (that disable the ignition so you don't need to ground the spark leads), open the throttle (fast idle lever) all the way up then check each hole by cranking for a few sec. You might get a higher reading like this and, anyway, 100 isn't that low and maybe related to the gauge you're using.

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

How do you check compression? Try it like this: warm the engine for a few min then stop it, remove all spark plugs, flip the kill swith (that disable the ignition so you don't need to ground the spark leads), open the throttle (fast idle lever) all the way up then check each hole by cranking for a few sec. You might get a higher reading like this and, anyway, 100 isn't that low and maybe related to the gauge you're using.

The design was similar for several years and I believe that factory new is 140lbs. I got that out of a 91 4 banger 100. If that still holds true on the 96's then 100lbs is pretty low.

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

I removed all plugs, open throttle all way, cranked for about 5 seconds till it built preasure. Im going to try to adjust carbs a bit tomorow and see if it will smoth out. It idles perfect for about 5 seconds when you start it from being cold, than stars bucking and running rough.

Chad

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

schaeffer i agree, i downloaded the shop manual, it says 150 - 180 , below one 120 could meen severe engine wear....thats what it says...i have rebuilt a dozen honda car engines, i know its completely diff but i think i will try to tackle it if it comes down to it.

If i could get it to idle better i could deal with it till winter. Unfortunately i just finished a restoration on the rest of the boat.

http://forums.iboats.com/showthread.php?p=2654505#post2654505

Chad

 

[Faztbullet]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Your test guage could be reading low and I would decarbon it first before anything..

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

schaeffer i agree, i downloaded the shop manual, it says 150 - 180 , below one 120 could meen severe engine wear....thats what it says...i have rebuilt a dozen honda car engines, i know its completely diff but i think i will try to tackle it if it comes down to it.

If i could get it to idle better i could deal with it till winter. Unfortunately i just finished a restoration on the rest of the boat.

http://forums.iboats.com/showthread.php?p=2654505#post2654505

Chad

Nice Fish Master, I've still got that MonArk Legend 1800 FS that I did two years ago.. Wow how time fly's.

With the compression that low, does she wheeze when you start it cold?

 

[saumon]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

schaeffer i agree, i downloaded the shop manual, it says 150 - 180 , below one 120 could meen severe engine wear....

Are you sure? I've never saw more than 135 on thoses triple...Maybe it's my gauge?

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Are you sure? I've never saw more than 135 on thoses triple...Maybe it's my gauge?

I'm pretty sure your right Saumon, box stock with a fresh bore and ring end gap set to .016 I got 140 on my 4 banger. 150-180 woud make it rough to find fuel for. Nonetheless, 100 is low. Since it's consistenly low across all three I'd have to agree that it's wear and not a carbon problem although I wouldn't completely rule it out.

 

[cc190cc]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Ok i can decarbon it, i will give it a shot, i was thinking that i should still be able to get the idle to smooth out even with the compression, considering its even.

Where can i buy a rebuild kit, i found a couple online just googling it but im not sure. I dont want to buy junk! Should i just rering it, new piston?? How many hours do you guys think this would take. Im just trying to put a realistic timeframe and cost on a rebuild.

Chad

 

[sschefer]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

Took me about a month of week nights and weekends to knock out a 100 but I just needed to hone it lightly. Parts are tough right now but I think if you PM FaztBullet he might be able to get you pointed in the right direction.

You won't know exactly what you need until you tear it down and check the bores. Once you have those numbers you'll know what your next steps are.

The bad idle could be low compression or excessive blow by. Try the decarb, it might get you through the season.

 

[saumon]

Re: 1996 Mercury 90HP 2 Stroke - 90ELPTO - carb/idle problem, WITH PICS!!!! HELP

To get an accurate price, you first need to remove the powerhead and split the crankcase to have a look at the cylinder walls. If they're scored, you'll need to rebore and, as thoses are blind holes, they can't be done at any 2-strokes shop.

It run from 60-80$ a hole and you'll also need matching pistons (120-150$, come with rings , pin and needle bearings), a master gasket kit (50-60$) and sealants. A flywheel puller (30$) is about the only speciality tool you'll need.

So, let's say 70$x3=210$ for reboring + 130$x3=390$ for pistons and another 100$ for gaskets, sealant and puller, it put you at 700$.

But, when you're at it, it's also a good idea to do the carbs, the fuel pump and at least the impeller so it will cost you another 100$ in parts.

For 800$, you'll have an almost new engine!