Altitude Sickness - 1995 200hp

[Never2Old]

Howdy, New to this forum and was hoping for some help. I?m working on a 1995 200hp that has come from near sea level to 6,000 foot elevation and is not quite performing as it should. My buddy and I are in the process of rebuilding the carbs and am needing to resize the jets for the new elevation. The two, yes two, manuals that have been bought don?t give us any direction on what size should be installed. Would anyone out there have any clue to the changes that need to happen?

I read one posting that suggested a decrease in the air jet of .004, an increase in the idle jet of .002, and a decrease in the high jet of .003, this was for a 1982 200 hp though. I know we need to keep the right mixture so no damage will occur to the motor. Any help or direction sure would be appreciated.

 

[tashasdaddy]

Re: Altitude Sickness - 1995 200hp

welcome to iboats. this is a controversial subject. as dealers have been telling people to reprop, rather than change the jets. i'm a sea level person. but i think the solution is rejetting, but i'm no help.
you may find your answer here"http://theoutboardwizard.bizhosting.com/johnson_evinrude_technical_help.html"

 

[ezeke]

Re: Altitude Sickness - 1995 200hp

Whatever you do, remember that the problem is lack of oxygen to mix with the fuel and don't do anything to reduce the supply of air or it will make things worse. Most of what I have read would indicate that reducing the fuel from the high speed orifice should be adequate at 6,000 feet.

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Thanks for the quick replys, it really helped. Tashasdaddy that link really provided some great info, fell right in line with what ezeke mentioned. Direction I got was to increase the high jets by .002 increments til it performs like it suppose to. Leaving the mid range and idle alone. Again Thanks for the help.

 

[tashasdaddy]

Re: Altitude Sickness - 1995 200hp

good luck, let us know how it comes out. we need more feedback on this subject.

 

[ezeke]

Re: Altitude Sickness - 1995 200hp

Just as a follow up, most of what I have heard and read about altitude and the changes it makes on engines of cars, planes and boats would indicate that the best that you can do is to keep the fuel mix at a level where it is not too lean and destructive to the engine, while not running so rich that the performance is bad.

Generally, the boat engines were simply not built and designed at or for high altitude so you cannot get the same performance. What that means to the boat owner is that you should be prepared to experiment some with the propeller.

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Already played with props from 25 to 19. Settled on a 21 pitch. Problem is the the motor falls on it's face when you try to accelerate, I end up choking it to keep it running. Once up on plane the motor runs great. It also idles nicely also. The impression I?ve got so far is that I need to work on the high end jet and my problems should solve themselves.

Thanks again for the insight.

 

[tashasdaddy]

Re: Altitude Sickness - 1995 200hp

make sure your cam follower roller is not damaged (see red arrow), the white part comes off, they are a known item that causes play in the linkage, also last time a link n sinc was done, this coordinates spark and fuel.

 

[walleyehed]

Re: Altitude Sickness - 1995 200hp

I go through this everytime I rebuild one and I'm at 3600ft.
The first step into this would be to drop 3 sizes for the mains @ 6000ft.
Falling on it's face on throttle-up is because vacume pulls air quicker than fuel...a hint that the idle mixture is a bit lean. .002 up (2 sizes) sounds like a good starting point..."IF" the idle circut is fuel and not air. You may also have a mid-range circut or bleed-air cross-over...the direction inwhich you go is dependant on which set-up you have.
I don't have my books here, but is this a crossflow?? I don't think it has the OIS ignition system either, does it??-this is important as well, because if you don't have the OIS, we need to advance the timing beyond max advance. How much?? we'll get to that when you determine it's not an OIS.

 

[tashasdaddy]

Re: Altitude Sickness - 1995 200hp

walleyehed, you've got far more experience with this, than this flat lander. it's all yours. i'm gonna watch it and learn.

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Thanks for the heads up walleyehed, I'll check the engine tonight and the Manual to determine if it is an OIS ignition system. Was wondering about the cross-over question, what should I be looking for? I always heard that you needed to advance the timing to compansate for the alttitude but never knew how much. Sure appreciate the help.

The cam follower is intact and appears to be in good shape.

 

[Dhadley]

Re: Altitude Sickness - 1995 200hp

The 95 200 does not have OIS ignition and the idle and md jets are air jets, not fuel jets. Make sure that you are running with the air silencer on, not off.

That picture has nothing to do with a 95 200 either, don't let it confuse you. (BTW -- the motor it's from isn't set up right either)

Also make sure you have Champion plugs and you're using 87 octane.

 

[walleyehed]

Re: Altitude Sickness - 1995 200hp

Thanks for the info on that DH!
With this info available, I can tell you the entire circuitry will be on the rich side, but to keep the idle smooth, you'll have to lean the idle circuit by going BIGGER with the idle-air bleeds, and I think .002 larger is a good place to start.
I would not mess with the mid-range jetting just yet...in cruise mode, this is where mixture will be the leanest...the 3500+/- range.
.003 smaller on the mains should be real good at 6k., and follow the advice of Dhadley on the plugs..Champion ONLY (correct P/N).
Max timing advance is maybe around 28 degs on that-should have a sticker saying what it is for sure.
I would check the timing static and if it's set right for sea-level, I think it should be around 2 deg retarded from max (In a static check)maybe even 3 degs less......for 6000ft, you'd be in a "safe" timing zone by advancing up to max in the static mode...... this will put us about 2-2-1/2 degs advanced from max under actual running conditions which is well within a safe limit of operation at 6000ft.
I run my '82 200 about 4 degs advanced at 3600ft., but DO NOT go that far unless you have a very experienced OMC Guru there while you're running it....in fact, just don't go that far.

 

[Dhadley]

Re: Altitude Sickness - 1995 200hp

I'm pretty sure on the 1995 V6 loopers the wot timing is 18*, better double check the service manual. I know, at sea level anyway, they don't like to be retarded much either -- they don't have a lot to start with. Lol!

 

[walleyehed]

Re: Altitude Sickness - 1995 200hp

I'm sure you're spot-on, DH...disadvantage of not having any look-ups at home, and thanks for the help on this.
I would follow the sticker on the engine for max timing and test to see that it is below that figure, static, to start with...at that point you can advance it to max in the static manner which will provide about 2 degs advance from max in the run-mode.
You still want to see about 5800+RPM on this at that elevation.
What RPM do you get as it is now?...and what prop?

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Thanks for all of the great direction, will be working through the timing this weekend and will let you know how it's going. I saw a posting a while back that gave this as the proper way to get the max timing set:

(Timing At Cranking Speed 4°)(J. Reeves)The full spark advance can be adjusted without have the engine running at near full throttle as follows. To set the timing on that engine, have the s/plugs out, and have the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary). Rig a spark tester and have the gap set to 7/16". Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4° less than what the engine calls for. I don't know the full spark advance setting your engine calls for, but to pick a figure, say your engine calls for 28°, set the timing at 24°. The reasoning for the 4° difference is that when the engine is actually running, due to the nature of the solid state ignition componets, the engine gains the extra 4°. If you set the engine to its true setting at cranking speed, when running it will advance beyond its limit by 4° which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place. No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting

Is this the best way to go? or should I just set it to the sticker value and call it good?

Thanks again for the help

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Forgot about the rpm question, since the motor is on a bass boat the hole shot is right now really slow with WOT rpm running at about 6,000 with a 21 pitch four blade prop.

 

[walleyehed]

Re: Altitude Sickness - 1995 200hp

Joe's timing advice is good...My experience has not shown 4 degs retarded doing the static check, but you'll be ok if when you check static and find that it IS 4 degs retarded, just advance 2 degs from there.

 

[Never2Old]

Re: Altitude Sickness - 1995 200hp

Hey again,
Been working on getting this motor set up and have a few more questions, While trying to set the timing by just cranking it I've used most of the screw to reach 18* BTC, per the engine sticker. Now since I'm easily confused, to adjust for the 4* difference in cranking versus running and the 2* adjustment for altitude, would I set the timing at 16* or 20* BTC?

Any and all help would be greatly appreciated. The only way to spend a Saturday when it's too cold to be on the water.

Steve