Logo

New Developments in 1987 140hp Evinrude not accelerating

I took the boat out the other day and it ran fine, accelerated perfectly. I took the boat out yesterday and its having a hard time accelerating yet again. The boat was at my mechanic and he said it ran perfect, which i believe because I saw it run perfectly. Its back there now because the issue is back

They cannot pick up a miss on the light, they are sure its not a fuel issue. When the motor runs and the pump the bulb it stalls out, so its not a fuel issue.

They thought it was a power pack because it sputters every once in a while at idle..Power pack was changed and its not the power pack, so they put the old one one..They think it could be a stator breaking up..

Motor goes to 3000rpms and takes a few seconds for the motor to go faster. Then it will go to 5000rpms and they hear the motor breaking up, but they cant get it on a light..

any ideas as to what is going on, now that we know its not a fuel related issue...

Thanks
 
Re: New Developments in 1987 140 Evinrude not accelerating

If your mechanic is telling you that pumping the primer, causing the engine to stall, is normal, you need to get a third opinion. (Racerone already gave you a correct second opinion.)
 
Re: New Developments in 1987 140 Evinrude not accelerating

I apologize, I miswrote, the motor did not stall upon pumping the bulb. I apologize. I wrote this thread quickly this morning. The mechanics are 10000 percent sure this is not fuel related, they even tried feeding each cylinder gas, and everything checked out OK. I had them put a new pick up in, and run new lines from the tank, to the water seperator, to the motor, only because the lines that were in the boat were about 10 years old, and it would have had to get done anyways.

Could it be a stator?? They just cant catch it on a light...
 
Re: New Developments in 1987 140 Evinrude not accelerating

I assume your mechanics have checked compression of all cylinders? What were the readings (1,2,3,4)?

Was the spark checked? With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Does it? Note that using spark plugs to check the spark is a waste of time.... the test gap of 7/16" is important.

Are you using Champion QL77JC4 plugs, gapped at .040? If not, do so for a try out. I know the latest recommended gap is .030 but the recommended gap for many years was the .040 setting.... sometimes it does make a difference.
 
Re: New Developments in 1987 140 Evinrude not accelerating

Racerone, what is your problem? Im here trying to learn and see what it could be and i get your wise ass comment. Chill my friend. Im sorry im not as mechanically advanced as you are


Anyways. The spark has been checked with the plugs out. And thosevare the plugs i have in the motor at the current moment.

Compression has been checked on all 4cyl. Compression is 120 on all 4
 
Re: New Developments in 1987 140 Evinrude not accelerating

I had the similar problem on my Nissan and no-one had been able to fix it for years! Call me with your info, and I'll give you some. P.S. mine is fixed! Read the entire thread under Nissan/Tohatsu titled: whats normal. TIMINATOR 623-877-8553
 
Racerone must have deleted his post.. hes comment was "let us know when "they fix it" Apparently racerone isnt enough of a man to step up to the plate, but he feels the need to delete his post on my thread....
 
You state that the spark has been checked with the plugs removed. Hopefully the spark jumped the 7/16" gap as I mentioned previously.... if not, that would be a problem. Good to hear that you have the proper QL77JC4 plugs installed. The compression of 120 on all four cylinders is great.

The spark plugs.... What do they look like and do they all look alike? Normal=Light Brown in color, Black=Weak spark, White=No ignition or water entry (Usual coloration).

The slow pickup in rpms from 3000 upwards could be either a sticking timer base (spark advance) under the flywheel which would slowly advance rather than spring instantly to the full spark advance position.... or.... a carburetor problem of sorts whereas fuel is not being supplied properly due to a improperly set float, a clogged high speed jet, or something floating around in a carburetor that would result in an intermitent problem.

The breakup at full throttle, if it is a very sharp breakup, would indicate an ignition problem. This has me wondering if the full spark advance timing is set too high, and if so, that would bring into the picture a pre-ignition scenario which will eventually result in damaged pistons etc. It would be a good idea to have that timing checked.

The stalling out problem you mention has me confused somewhat... Does this stalling out occur right after the full throttle break up takes place, or when the throttle is first applied, what?
 
Last edited:
Yes the the spark jumped the 7/16" gap as you had previously mention. The spark is good, the timing is dead on. Timing has been checked 4 times.

The 3k sounded and left like fuel to me too. It kind of feels like when you have a motor that hasnt run in a while, and the carbs are dirty, and you go to get up on plane and it just doesnt go, but as fuel runs through the carb it cleans it and fixes itself in no time.. The motor was run before the carb rebuild, and after the rebuild as well. There is NO difference after it has been rebuilt in the performance..

The spark plugs are light brown, and there is no signs of water on the plugs or in the plug holes.

The break up at WOT is not a sharp break up. Its sharp enough that you can hear it, but it cannot be picked up on a light. At 5000rpms the motor puts out a ton of power and hums, it sounds nice a smooth. anything above 5000rpms and the motor sounds rough and is very sluggish on acceleration..

The motor is not really stalling out as in shutting down. I dont know the correct terms to use. The motor more or less hesitates at 3000rpms..
Its funny. At first I thought it was a prop problem, when that was ruled out, I thought it was a fuel problem. So what I did was, I ran the motor on a portable tank..When to go get up on plane and there was NO hesitation, the motor ran perfectly, no WOT break up.. I jumped off plane put the motor in neutral for a second, went back and tried to get up on plane again..boat planes with no issues, WOT was 5500rpms, boat ran great..I took the boat into the mechanic to have him change all the fuel lines and pick up..Before he touched anything, we both went out on the boat so he could see how it was "fixed" I go to get on plane and the motor wont go above 3k, 3-5 seconds later the boat just jumps up on plane, and the WOT break up was back..And this was running with the portable tank. Tell me that isnt weird..

My mechanic had a similar issue with a 70hp Johnson. Couldnt find anything on the light, and fuel was ruled out..He changed parts left and right..Finally he changed the voltage regulator, the tach was working and the battery was taking and holding a charge..so why would it be a voltage regulator? So he changed it, and the voltage regulator fixed the problem..

People on this board told me to get a new mechanic and find someone who knows what they are talking about.
My mechanic is a great mechanic, he is well known and has been in business for years. I have been going to him since I am 8 years old. I am now 29, so Ive been there for a while. The shop is stumped, they called another outboard yard and had them come down to take a look at it, and he couldnt figure it out either, and they ruled out that it is definitely not a fuel issue

Weird....


 
Yea, weird is a good word for it. BTW.... very good explanatory post you put up there, leaves nothing to the immagination, really spells it out.

The full spark advance timing..... hopefully that is being checked out on the water and running under way OR with a test prop. If checking it via the method that I came up with (setting the timing at cranking speed), the timing would be required to be set 4° less than what the manual states.

The 3000 rpm hesitation problem that apparently is intermitent.... That would have me looking very closely at the timing base for a sticking problem.

You mention above running at 3000 rpm and 3 or 5 seconds later, the boat just jumps up on a plane. If that jump up in rpms was an instantanous jump, like two cylinders cutting in all of a sudden.... that would lead me into the timer sensor area on the timer base. One sensor fires the starboard bank, the other sensor fires the port bank... check them for their proper ohm readings, and also check all of the rubber plugs associated with the ignition.

The figure of 3000 rpm is approximately what you could obtain (in time) running on two cylinders.

The rubber plug connectors have pins/sockets setup, both of which have been know to become pushed back somewhat as time goes by which results in poor intermitent contacts. Also the wires themselves break off from the pins/sockets but stay within the rubber plugs giving the illusion that the wire is connected when it is not. This is a problem that I've encountered time and time again.
 
Last edited:
The full spark advancement has been checked out on the bay while underway.

Now, if its a spring sticking on the timing base, that would explain the 3000rpm issue, BUT would that explain the 5100rpm issue, or are we dealing with two different animals here??

Yes, while waiting at 3000rpms for those few seconds, the RPMS do jump as if two cylinders are just catching up..Its an instantaneous jump..Like I said, once the motor "catches up" with the throttle its hold on because the boat takes off..Now, as I asked above, if its a sensor, would that cause the 5100rpm break up, or is that from something else?? Could it be related?? I will check the ohm on Sunday or Monday and I will report back. Myself and the mechanics are at a point where there isnt a whole lot to test. Im not saying they are losing interest, its just what do they do next? Just throw parts at it till something clicks and works??

The rubber plug connectors have all been replaced. Ive even swapped them off another motor, and had no difference..

Its such a weird problem..
 
If you're sure the pins/sockets are making perfect contact, that eliminates that possibility.

The sensor and the 5000 rpm problem could be related. If a sensor is malfunctioning or has a frayed wire, that would have weird effects on the two cylinders that it fires.
 
Took the boat back out again today, to put some gas into the tank. The motor is running worse, but still cannot pick up anything on a light..

Heres what its doing..

Again, it goes to 3000rpms, but now it takes 9-11 seconds for the boat to really get up on plane..At 3000rpms the bow is all the way up..Once running on plane, the power is good. Today for some reason I couldnt get close to 5500rpms..It was getting up between 4200-5000. I was able to hit 5000 once today, and that was WOT..At WOT I was getting 35.5mph, and the motor sounded terrible..Now heres the kicker..Once I back off the throttle ever so lightly, the RPMS jumped from 4200rpms up to 4700rpms and I gained 1mph, so 36.5..Once I put the throttle back down, the boat like slowly slowed done and dropped to 4500rpms and lost about 1.5mph..

When I backed off the throttle the motor went from sounding terrible back to the humming and sounding beautiful..

This is the WORST I have seen this motor run..
 
Your latest explanation would indicates that either the timing is too far advanced or the throttle butterflies are exceeding the full horizontal (full throttle) position and are starting to close again.
 
Timing was checked again, and its dead on. Also checked the throttle butterflies and it does not go past full throttle..

Could it be bad reeds????
 
Off the top of my head, after everything that has been said, I can't think of anything else to add, sorry. Hopefully another member will jump in here with something I may have overlooked.
 
Second thread, same issue. Post pictures of your setup the Guys here will help you with your cooperation.
I am posting again even you and I went off to a bad start on the previous thread on this same issue. Never a hard feelings just trying to help...
I will ask you again answer if you like or not.
How many splines on your PROP? Reason you ask? I have seen the wrong LU (v6) bolted up on V4 it will never run correctly if the gear ratio is incorrect. Note some V4 were shipped with the V6 gear case however the ratio must be for a V4.
Post the numbers on your idle, intermediate and high speed jets ? Reason you ask Because this matters for performance and acceleration.
Post the number of screws you see on your butterflies ? Reason you ask? Maybe some bolted up 120 cards ?
 
Sorry for not getting back to you sooner. Ive been on the road traveling.

There are 13splines, on the prop, and the same on the shaft.

I wont be able to get pictures till later on next week but I will try to get them sooner.

If it was a v6 gear case, and the gears were not the right ratio, would this problem happen sometimes, and other times it would run perfect? Thats whats going on now. Though its running bad more then it runs good.

The carbs were completely taken off for rebuild, and the intake gasket was replaced. The motor ran the same before and after the carbs were rebuilt. The crank case seal and gasket are "A" ok no leaks
 
If it were mine, I would finally resort to the dreaded "shotgun approach." I would substitute the timer base, stator, and powerpack from another engine & see if problem goes away. If not, I would then try a set of carbs from another engine. If you buy right on Ebay, each option should cost less than $100. I had a 235 that I rebuilt the carbs on 3X, still ran poorly. Put a different set on, ran perfectly. Never did find out why.
 
carbs have been swapped on with a 120hp carb set, HOWEVER, all the jets were replaced with 140 jets.

get ready for this........timing base, stator, and power pack were all swapped out from another running motor, AS WELL AS brand new parts, and it did not change how the motor ran..

The stator that was on MY motor, was also put on ANOTHER motor, and tested that way. That worked perfectly. Same thing with the timer base and power packs. Even the coils. EVERY part of the ignition system has been swapped out..

This motor is going to be the death of me...
 
Thanks for the updated information. You need to use a caliper and measure the venturi and post the measurements. Maybe big bore looper carbs bolted up?
Its very important you post your jets sizes, idle, intermediates and high speed.
This engine is notorious for stumbling at mid range and getting up on a plane, if you stab on the throttle it will get up and run correct?
Which set of carbs are you running ? Note 397908 and 397907 is a set port and starboard.

If you have this set install make sure your intermediates are all .16, Idle set to Stock and High stock also...
Models With 397908 Stamped in Cover Plate (Starboard) ?
Models with 397907 Stamped in Cover Plate (Port)?

Models With 431883 Stamped in Cover Plate (Port and Starboard) Post jet sizes please ?

This Year/Model can be a PIA to dial in on the correct jets, I own both beauties from this this Year .. ( E140TLCUA & E140TXCUA) so I know ...You will nail it hang in there...
 
You can swap 120 and 140 carbs but the jet sizes must remain in the carb they were produced with. IE, 120 carbs need 120 jets no matter what motor they're on, same with 140 carbs & jets. And when we say carb we mean carb assembly. If a 120 carb body is put on a 140 throttle body, or vise versa, all kinds of wierd things can happen.

Also you mention several times that the timing is correct but never say what it's actually set at. It would be helpful to know.

Another good clue is when you mention backing off slightly and it runs better. The carb butterflies need to go slightly less than perfectly straight. They need to stop just short of perfectly straight so that they "hide" the emulsion tube slightly. And the airbox cover must be on. If it's off it changes the calibration dramatically.

And speaking of emulsion tubes, make sure they are in perfect shape. Look down the throat of each carb, each tube should be at the same height in carbs that are alike. And they should not be broken, cracked or split.

Sometimes it sounds like you're describing a motor running with a leaking fuel pump diaphram but since you say the plugs are all the same color we can rule that out.
 
Last edited:
A thought just came back to me from many years ago, a once in some thirty plus years encounter. I once encountered a engine problem whereas the problem wasn't the engine but rather a control box problem. I don't recall the exact problem within the control box but it had something to do with the control handle being pressed to full throttle..... something like the drum of the throttle handle assembly interfering with the ignition switch contacts.

Grabbing for a straw..... it might be worth a shot to remove the black/yellow wire from the ignition switch (eliminating the switch kill circuit) to see if that has an effect on the problem.

When I was young, and one of the gang or I would have a weird problem with their car, the standing joke was to jack up the radiator cap and drive another Chevy under it.
 
BTW just so you know the 120 HP has different jets, smaller venturi (2 screws on butterfly) 4 petal reeds. I am not sure how you just swap the carbs and expected to see it run correctly..
 
Well...did you find the problem? I have '85 140 Johnson that is having same issue as your engine. Hoping to gain a little hint from this thread.
Thanks
 
Back
Top