98 Ocean Pro 200 losing spark at #3 & #4 cylinders intermittently

[horboroaks]

My 1998 Johnson/Evinrude 200hp 2 stroke outboard is losing spark at #3 and #4 cylinders. At idle it will die when it happens, and if i try to hold a 1500 rpm idle it will drop to 1300, and 1400 and back with spark cutting.in and out. At i higher throttle 2500+ i have spark. I used a spark tester and found those cylinders cutting out and back on, but will idle fine when fired up for the first 30 seconds, then spark is lost and it stalls It confuses me how it happens intermittently

 

[horboroaks]

Sorry about posting this six times in a row... I have no clue why it Did That. I posted from my phone -

 

[daselbee]

Well, it is a known problem that these engines can drop a cylinder exactly when Quick Start drops out.
Now, you say 30 seconds....does this correspond to the exact time QS drops out, is this a guesstimate of the exact time, or what?

Last time this happened to me, it was #2. As soon as QS dropped out, #2 would go no spark.
You would think it was the powerpack. Nope.

It was the timerbase. Absolutely guaranteed. I still have that bad timerbase as a souvenir!!!

 

[horboroaks]

Yes as soon as the Quick Start drops out...

 

[horboroaks]

I had a corrosion problem that made things worse. I have cleaned all connectors. I had a problem at the black yellow and Black orange wire connector, it wouldnt shut off It was corroded so bad. The coil wires on 5 & 6 were really bad. Could my 3&4 coils not be grounded good?

 

[daselbee]

Well, coils get their ground from the engine block, and the attaching bolts. So clean them up and see what happens.

Exactly when QS drops out? To me it is as I stated above....timer base. But, I have never seen a TB drop two cylinders when QS drops out.

Pull the rubber connectors apart that run from the TB to the pack. They are black, round four wire, and are located under the pack.

Examine very carefully the pin positions (not pushed back), the pin and socket quality (are they bent up), etc. There are two of these connectors.
One for each "side" or bank of cylinders. Looking at one of them, the blue wire is for the top cylinder trigger signal, the purple is for the middle cylinder, and the green is for the bottom cylinder.

So you would be looking for specific problems on the two purple wires for intermittent #3 and #4 problems.

I still think it is too coincidental that they drop out exactly when QS quits.

But all the wire inspection and cleanup is free. A Tb is a few bucks.....

 

[horboroaks]

The coil grounds were corroded bad, so we the bolt holes on the electronic box under the cdi box and cdi box ground was bad. I got it to idle steady on ears and ran good. Took it to ramp and had to adjust the carbs to 3 and 1/2 turns each and it idled a little high i thought (1000-1100 Rpms) We went for a ride and it ran good until we tried to turn around at low throttle it stalled, then it didnt want to stay running, would bog when we gave it gas. Total fail.

 

[horboroaks]

I just fired it up Cold and on the ears in driveway and it ran great, idled for 15 mins, shut it off, restarted it , gave it throttle a few times it was running good, so o let it idle another 15 mins, it never got hot, but once i. A while i would get a hickup and idle would drop to 750 and work its way back to 850-900. I am running Off a portable tank By the way

 

[daselbee]

Idle mix screws should be around 5-6 turns out. If you are at 3-1/2, something is wrong.

You clean the throttle bodies, behind those flat metal plates held on by 4 small Phillips screws?

 

[horboroaks]

I cleaned the heck out if the throttle body, but it wasnt dirty really. 5 1/2 turns? Allover the internet it said 3 1/2. Would that cause all my ptoblems? I could see at idle but it wouldnt even take throttle or start and run with some throttle

 

[daselbee]

You have a 98 200....same as the 96 200 and starting point would be 5-1/2 turns., from the book.
From 96 forward til the end of production of the Johnson V6 loopers (2001???), the design was pretty much fixed...no changes.

From late 80s til 1996 the carb design was constantly changing.

But....turn them all out to 5-1/2...can't hurt a thing. You can always put them back.

How did you clean the throttle bodies....when I ask this, I would expect the answer to be that you removed the small plate and cleaned out the 5 very tiny holes that bleed fuel to the engine at idle. I have to use a welding tip cleaning wire to do the job.

The only problem with my thinking on this is that it is backwards....if those holes are clogged, you generally have to turn the idle screws OUT to get more fuel flow through that circuit.
So you needing 3-1/2 turns is backwards. 3-1/2 turns results in less fuel to mix with the supply of air. At 3-1/2 turns, it should be lean sneezing.
Do you have the correct idle air bleed jets installed? Should be #27s if I remember right.

But, if the idle circuits are clean, you could be way lean right now, and all that is needed is to richen it up to 5-1/2 (or whatever is the optimum for your engine)..

Try it.

You didn't out and out state it....did you fix the intermittent spark on #3 and #4? Did cleaning the corrosion from the coils fix it? If so, why was it dropping spark on those 2 cyls only when QS dropped out? If corrosion was the problem, they would be intermittent/dead all the time.

 

[daselbee]

I cleaned the heck out if the throttle body, but it wasnt dirty really. 5 1/2 turns? Allover the internet it said 3 1/2. Would that cause all my ptoblems? I could see at idle but it wouldnt even take throttle or start and run with some throttle

Direct answer to your question...YES. The fuel for idle as well as for the transition up tot maybe 2500 RPMs comes thru that throttle body side plate labyrinth.

Examine it closely, follow the fuel path. Be sure the brass tubes that stick down into the carb bowls are clean. They taper up at the top to a small hole that can get varnished up badly.

The fuel for the engine operation that you are having problems with comes thru there.

 

[horboroaks]

I rebuilt the carbs a week ago; I disassembled them, cleaned and blew out everything, new valve seats, floats, needles, gaskets. The carb air mixtures were "around"3 and 1/2 to begin with so it sounded like a good place to start. I really dont seem to be having a fuel problem. When its on the ears it runs great now, just falls on its face under a load after running it enough to build up a higher core temp. It was like the timing was off if it was an old chevy truck On the road... like the timer base is wacked

 

[horboroaks]

I definitely cleaned behind the plates though, and replaced the gaskets, blew out pin holes and poked wire through everything. And YES after cleaning coils and "everything" elelectrical spark in all cylinder is consistent

 

[daselbee]

Ok....whatever you say. This isn't an old Chevy truck.

 

[horboroaks]

LoL im just saying thats how it ran in the water II am going to go to 5 1/2 turns What got me was in the water it was fine for the first 1/2 mile and then it would only start and die, bowls were full. And when it cooled all the way down it was normal again

 

[horboroaks]

LoL i was just saying thats what it run, like the timing was off as in a chevy V8 What is so difficult for me to understand is how after I got it home and on the ears it starts runs and idles perfect

 

[horboroaks]

LOL I was just saying thats how it ran like, What I dont understand is how after it cooled all the way back down it started, ran, and idled perfect ( on the ears) It happened after we run it a half mile at 3000rpns... And hasnt happened again

 

[horboroaks]

LOL I was just saying thats how it ran like, What I dont understand is how after it cooled all the way back down it started, ran, and idled perfect ( on the ears) It happened after we run it a half mile at 3000rpns... And hasnt happened again at home in the driveway

 

[horboroaks]

LoL i was saying it ran like a chevy truck out of time after it was fully warmed up What I dont get is after it was home cooled all the way down, it started ran and idled perfect on the ears