Evinrude 1986 225 Carb flat spot/stalling

[Dhadley]

Re: Evinrude 1986 225 Carb flat spot/stalling

Rejetting will be the last thing you do, not the first. If all this checks out then it's time to look at jetting. But you have to go thru these steps first.

Have you reseated the butterflies yet?

 

[Captain Koz]

Re: Evinrude 1986 225 Carb flat spot/stalling

hello,
Havent forgotten about everyone here. Long Island NY has been experiencing really nasty weather. Either nasty cold, or rain, or icy rain, or a combo of all. Im just waiting for a tollerable day to go out and tweak. I am anxious to finish this thread!

 

[Dhadley]

Re: Evinrude 1986 225 Carb flat spot/stalling

Have you reseated the butterflies?

 

[Captain Koz]

Re: Evinrude 1986 225 Carb flat spot/stalling

Yes, today i reset the butterflies AGAIN. this time however I paid particuar attention to the position of the butterflies. Turns out that due to the play in a 22 year old carbs, the butterfly valves - properly adjusted as per manual procedure- amount to the starbord bank opening slightly before the port bank due to the connecting arm between the banks creating play... and thus lag to the port bank. So it took me a few tries to determine what is moving when to get the setting just right to where they are opening at the same time despite the play. I am doing it visually because at this point there is no way to do it mechanically (other than flow testing) however I think I got them perfectly. I tried to do it with the motor running but the vibration and the slight misting of fuel in my eyes that close to the carbs made it impossible. Last time i did it by the book with the motor running and I thought it was ok. I now cannot notice any difference in the point of origin of movement between the banks. Keep in mind all of this is happening in my driveway out of the water on a trailer. It makes it impossible to hear or feel any slight differences in how the motor performs. The only way to see what works or not is an in water test. In the driveway... it runs... and thats about all you can tell.
I must admit that the banks were every so slightly off from one another when synced by the book due to the play. I had to study them closely, but I determined a difference. Now there is no difference. they appear dead on. I am hoping to get the boat in the water tomorrow to see if it made a difference. Stay tuned

 

[Captain Koz]

Re: Evinrude 1986 225 Carb flat spot/stalling

Just got back in from water testing it. What I did besides resetting the butterflies was to insert 26 gauge craft wire into eash #20 Jet, wrapped it around the jet, then had the end hang over the edge of the carb so the foam gasket of the intake cover would hold it in place. Basically I used a modified concept of placing "toothpicks" in the jets to richen them up. However I didnt want to completely close off the jet, just restrict it a bit. I estimate the wire closed the jet off more than 75%. Well, finally... after 3 months of trying, i finally have a motor that runs right. She is smootheeee... perfect, maybe a bit rich and lethargic but I anticipated that due to the size of the wire. Finally, a motor i didnt recognize... one that throttled up and down without going flat. Even the idol smoothed out. Heaven. BUT... yes, its temporary and YES... shes running rich. Just for sanity sake, I wanted to check and see the impact of re-syncing the carbs. So i dropped the anchor, took the airbox cover off, removed the wires from the jets, put it all back together and ran it... to return to the same nightmare I started with. Nervous through the first 1/4 throttle then the flat spot, dying at the flat spot, choke, then throttle up for smoothness in the upper.
So at least ive confirmed that richer jets will solve what is going on. Keep in mind I do not know what is causing it to lean JUST in the idle circut, but after I rejet it i dont really think I will care much. OF course the jets didnt come in friday and they are closed monday so im looking at maybe tuesday. I am concerned at how well it ran with such a drastic reduction in flow (remember I think the wire blocked about 75% of the jet opening). Im not sure a drop to #16 will do it. I will try it first. There are always #14's and if thats no good I will resort to soldering the jets closed and drilling them with a micro drill bit. But im thinking 3 steps ahead as usual (keeps me optimistic). Basically I have confirmed that smaller jets(richening the idle circuit) will get the motor to work right. WHY its leaning is another story. After jetting I dont think I will really care why, but, I am always open to all your suggestions and will be willing to try anything else that makes sense.

 

[johnhot]

Re: Evinrude 1986 225 Carb flat spot/stalling

Just a perhaps unrelated thought...when I installed Boyesen reeds in my 1988 Johnson 48 SPL their tech support told me I would have to richen the idle mixture by reducing the jet size 5 steps. Don't know if that relates to your situation or not.

 

[Captain Koz]

Re: Evinrude 1986 225 Carb flat spot/stalling

Thanks Johnhot. 5 steps would put me at a # 15 which apparently doesnt exist (#14, 16, 20..etc). In 88 i think they moved the jets into the 30's (# 34 and 37). I dont know why but I would assume it is easier to maintain a motor with larger orifices against clogging .I installed the #16's and then seem to have done the trick. The boat runs awesome now... but I am still puzzled as to what is causing it. Im suspecting a crack or leak somewhere. On my next free (and warmer) day I plan on test tanking the engine, running her, and "painting" every joint/seem with a paintbrush of soapy water to see if I get any bubbling. Otherwise she now runs acceptably.

 

[cfauvel]

Re: Evinrude 1986 225 Carb flat spot/stalling

Having similar issues with my '86 225 hp evinrude

I just recently got a new stator, power pack and timer base, just to get the thing running . But am having a similar issue, once started and warmed up it has a lean pop/sneeze at idle, sometimes conking out.

Funny thing is that it is hard to start initially and when it does there is a lot of smoke. Once warmed the smoke is alot less, but has the lean pop...not sure yet which cylinder it is ...but will keep trying to figure it out.

I'm going to try your wire trick on the idle bleeds tomorrow.

My motor is a 1986, but has 1987 carbs on it. My mech friend said that '86s had idle problems so the fix was to put '87 carbs on under warranty.

the '86 carbs state the jets should be 14 (intmd), 20 (idle), but the '87 carbs state they should be 14(intrmd) , 48 (idle)

my engine was rebuilt in 93 and the mech in miami put on 47s but in the wrong spot. He had them 47(intermd), 14 (idle), thus lost the 48s. I started messing with the jets to idle better and stop the excessive smoke.

I bought a set of 20s before I was told that I had '87 carbs on. So at least I have this set, but going to 20s from 47s seems pretty drastic., but swapping what the previous mech did in Miami was drastic too. He may have been onto something...the damn motor hasn't idled well since I've owned it back in '92.

erring on the side of what the manual and parts blow state I have 14(intermd) and 47(idle, as close as I can get with parts on hand) currently.

I too am running the QL77JC4 plugs, they are pretty fouled though..going to buy new ones tomorrow.

I'll be doing the wire test tomorrow as well to narrow down which cylinder is running too lean.

$7.00 per jet, come on!!

 

[rodbolt]

Re: Evinrude 1986 225 Carb flat spot/stalling

Cfauvel
try not to jump threads. makes it less confusing.
but do all the above checks that Dhadley stated before playing with jetting.
however the looper V motors and some of the cross flow engines of the mid 80's to the mid ninties sometimes needed jetting adjustments to smooth them out.
you have to remember most techs never really understood carbs with fixed jetting and manufacturing tolerances.
you may also find, if you have a good dealer, many other carbs used the same diminsionally sized jets with the exception of the bore.
sometimes you buy a way smaller size then use a wire drill to lean out the fuel .
it can be time consuming but well worth the effort when your done.
back in the late 90's I bought a rig with a 120 small bore looper.
got it dirt cheap cause the guy was mad cause it would not idle correctly and he could not troll.
after fixing all the accumulated technician induced issues I played with the jetting for several hours.
in the end I had a sweet running 120 that would idle all day at 650 RPM and accelerate smoothly.
key is make sure all mechanical parts are in good shape, make sure all linkage adjustments are correct before playing with jetting.
but yes we had several motors that out of the box we had to play with jetting to make the idle to our dealerships satisfaction.
better for us to do it before the customer came back complaing about the cough at idle or the stumble at throttle up.

 

[Faztbullet]

Re: Evinrude 1986 225 Carb flat spot/stalling

Have someone pump the bulb as you plane off ,if it quits bogging and flat spot goes away,replace VRO pump. These carbs only hold a little over 3/4 oz of fuel due to small bowls. If this helped, the problem is engine going lean due to lack of fuel in carb. I have seen this many times. Do not use a aftermarket carb kit has I have found some of the needle and seats are restrictive and cannot flow enough fuel. To test this run at WOT and hold in choke, if engine gains rpm it's to lean. I use a different needle and seat.

 

[cfauvel]

Re: Evinrude 1986 225 Carb flat spot/stalling

Cfauvel
try not to jump threads. makes it less confusing./QUOTE]

Sorry about that, wasn't trying to start a new thread but remarking on the similar problem I'm having..Right now it hasn't manefested into the stalling, because I haven't tested the boat in the water yet. Just trying to get it to idle nicely without sneeze on land.

Should I start a new thread?

 

[Faztbullet]

Re: Evinrude 1986 225 Carb flat spot/stalling

You cant fine tune on a hose, engine has to have backpressure. Stick in a trashcan if lake to far.

 

[cfauvel]

Re: Evinrude 1986 225 Carb flat spot/stalling

Just an update, with the idle speed set incorrectly (more on that later) I finally foudn the lean pop to be two things...a cracked fuel manifold and the use of the nylon washer under the needle's seat. If the carb's has a ring where the needle seat goes the nylon washer is not used.

That fixed the lean pop on muffs, on the water the engine would not idle at the speed of 1000 ste on land...had to adjust idle speed to 1200 to keep it running.



But I think I found that latest issue.

It appears that after all of these years I have been adjusting the idle speed all wrong. I have been using the idle stop screw that is on the same lever as the WOT stop screw to adjust the idle speed. which cracks open the butterflies.

It appears that for 86-86 v6 engines the idle speed is actually adjusted from the timer base screw that is just below the flywheel. The screw in question is at the end of a cigar looking thing that has a wire that pulls the lever of the timer base. Not WOT max timing stop screw which is even MORE under the flywheel.

With the butterflies completely closed now, the idle aire bleeds are doing the metering of the air. The engine is noticeable more rich at idle . The screw in question had to moved about an inch counterclockwise to get the speed as I originaly had it, 1100rpm.

Will test sometime this weekend to be sure... I too bought a whole bunch of idle air bleeds to adjust the jetting to be more rich....original jets were 48 for these '87 carbs on a '86 enigne, but currently have 47, and was going to try 40,44, 35. Now I need to go back up to 48, though I doubt that will make much of a difference.