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1987 Evinrude 140hp Looper Not accelerating

Hey all

First time on this site and I have found it very useful so far.

I just bought a 1987 140 HP Looper. compression is 125psi on each cylinder. I have been told thats not good compression, and I disagree. I think thats very good compression.

My problem is, with acceleration. When I go to get up on plane the bow jumps up but it does not plane. If you count to 5 the boat will rocket out of the water. I just rebuilt the carbs and that seemed to help the acceleration but its still hesitating. Also, when I am 3/4 throttle, and I go to WOT, it still hesitates before the extra power comes in.

Right now I am spinning a 14X19 prop and I am turning 6000rpms. I know thats too much So I am going to go to a 13.3/4 X 21 prop, to bring the rpms back down.

What else should I look for as to my problems with accelerating? Its a great running motor just this little hicup..

Any thoughts??

Thanks
 
Re: 1987 Evinrude 140 Looper Not accelerating

First get the correct prop on the engine. Do you have the engine trimmed properly on the boat?
 
Re: 1987 Evinrude 140 Looper Not accelerating

Yes. I have the motor properly trimmed. I had the motor all the way down, and then once the boat goes up on plane thats when I trim the motor. When I trim the motor, thats when it runs up to 6000rpms. When I leave the motor down I turn 5500rpms..

I didnt want to go the prop route just yet because trimmed down I turn the proper amount of rpms...

I talked with another guy who had a similar motor and he experienced similar problems. He said it could be a bad fuel pump..Would a pump cause the hesitation?
 
Re: 1987 Evinrude 140 Looper Not accelerating

The other guy said his pump was weak causing unregulated fuel pressure in the carbs. Not likely a weak pump causes unregulted fuel pressure.

Anyway back to your motor. 125 is good for compression. We're not concerned too much about actual numbers but rather differences. You don't want to see more than 15 lbs between high and low, you're even so you're good. Don't be afraid of 6000 rpm with that motor. The rev limiter is at either 6200 or 6700. You're OK for now there.

First make sure you never run the motor under a load with the airbox cover off. That makes the motor run very lean. A float out of adjustment may cause a bog too. Verify those 2 things first before going on. Don't assume a mechanic got the float adjustment right.

If those things check out look at a few things -
1- verify the jets are all the correct ones
2- make sure you have fresh 87 octane. 4 week old fuel is not fresh.
3- use Champion plugs only. The QL77JC4 is a good choice with todays fuel.
4- how is the idle? Any coughing or stalling?
5- when the motor starts to bog if you tap the primer (choke), does it pick up rpm?
6- verify the sync & link (including timing). Again, don't assume.

Let's start here. Let us know what you find.
 
Re: 1987 Evinrude 140 Looper Not accelerating

The air box cover is on. Its all tight, no leaks, its totally sealed. The floats are also all properly adjusted. The jets are the correct size, I was able to check that.

Though, I dont have 87 in the tank, I run my outboards on 89. Ive ran them on 89 for years and I have had much better results. Plus, I hear outboards like 89 more so then 87.. I dont know if there is any truth to that.

I actually have those exact plugs in the motor, I replaced the plugs about two weeks ago with brand new ones. Idle is PERFECT, idles smoothly, no hicups, vibrations, or anything like that.

Its not that the motoris bogging, it only goes so fast for so long, before it turns to a rocket launch.. The sync and timing are exactly what it should be..
 
Re: 1987 Evinrude 140 Looper Not accelerating

Is the timer base good and free and workng properly when you snap the throttle ?
 
Re: 1987 Evinrude 140 Looper Not accelerating

Yes, everything is working properly in those regards. I guess thats why its so puzzling. Everything is working as it should, its just not performing the way it should.

I know its not a clogged fuel line or pick up, I had a Force on the boat before the looper and the force was terrific. Only thing I can think of is that the force was a 2 carb motor, where the looper is 4 carb and requires more fuel at once...?

I dont know where else to look / test
 
Re: 1987 Evinrude 140 Looper Not accelerating

There have been issues with the crankshaft sealing ring on those loopers.--------------------Have someone check them out.
 
Re: 1987 Evinrude 140 Looper Not accelerating

Just putting my 5 cents here...

Make sure none of the rubber/nylon fuel lines in the engine compartment are pinched by some cover / air silencer box / etc. (as it happened to me :))
Also, if your carbs have adjustable slow speed needles, try twisting them out some more and see if it behaves the same way (I'm pretty sure you fine tuned IDLE properly as instruction specify. I had similar problem, until I discovered that it's better to adjust SS needle when the motor is under load at very low RPMs). Just do it for try and error fun ;-)
 
Re: 1987 Evinrude 140 Looper Not accelerating

Ill try that. Not a bad idea. At this point I am willing to try pretty much anything to get this motor performing as it should. Thank you..

Anything else to try while I am digging into it??
 
Re: 1987 Evinrude 140 Looper Not accelerating

Well if the 6 crankshaft sealing rings are checked to be OK, then the next step is to pull the fuel pump apart and check the following. ---The air motor piston and the fuel piston diaphragms. Or have someone pump the bulb during operation ( manual fuel pump ) and see if lack of fuel is the problem.------------Put a timing light on this thing ( each cylinder ) and see if you have steady spark up to full throttle.-----You have had the high speed jets out to verify that they are spotlessly clean.---------Shine a strong flashlight into each carburetor bore during acceleration to see how fuel coming up the high speed nozzle behaves.------Just finished a 120 looper and the owner said " i have owned it for 2 years and it never ran as good as that "
 
Re: 1987 Evinrude 140 Looper Not accelerating

I have a brand new fuel pump. Instead of taking the old one apart, can I just replace the fuel pump and see if that fixes the issue?
 
Re: 1987 Evinrude 140 Looper Not accelerating

First of all I do not believe that the 87 -140 HP has adjustable low speed jets.------------It has idle air bleed orifice plugs and they are easy to mix up so check them.---------------The bulb on the hose is a " manual fuel pump " ---have an assistant operate that while you attempt acceleration.
 
Re: 1987 Evinrude 140 Looper Not accelerating

You are correct, this motor does not have low speed jets.

"idle air bleed orifice plugs and they are easy to mix up so check them" Now we are talking a foreign language here. No idea where those would be.

Ive tried the pumping of the primer bulb while acceleration and that does not seem to make a difference..
 
Re: 1987 Evinrude 140 Looper Not accelerating

He's talking about the low and mid range jets like we talked about before. Make sure the numbers on the jets are all in the right place. It will help if you post what number jets are where.
 
Re: 1987 Evinrude 140 Looper Not accelerating

Also, from what you describe we may have an ignition issue. If the motor is running on 2 or 3 cylinders it will be slow as you describe. Once the other cylinders kick in it will "launch" like you describe. Something to think about....
 
Re: 1987 Evinrude 140 Looper Not accelerating

Not sure if this applies but here goes. Does your motor have a roller that sits in a cam slot for the spark advance? If so, that roller wears out and will cause a delay in the timer base going to full advance. It creates a lot of slop in the adjustment and will give you problems getting on plane. Been there and replacing the roller solved the problem. That was on a 1992 115 TLEND. Hope this helps.
 
Re: 1987 Evinrude 140 Looper Not accelerating

If its an ignition issue, what elements can be tested / changed to fix the issue? If I have a cyliner or two down, can that even be fixed? Im in no way close to being handy with motors. I can do basic carb work, (though I dont know what numbers your talking about with the jets). I can adjust idle..much more then that requires me going to a friend to help...
 
Re: 1987 Evinrude 140 Looper Not accelerating

Earlier in the thread you said you checked the jets and they are all the right sizes. The size is the number stamped on each jet. If you don't know the jet number you can't verify if they are correct. Post the numbers stamped on each one so we can verify their correct size for idle, mid range and high speed.

Also, when you say you can adjust the idle, how are you adjusting the idle?
 
Re: 1987 Evinrude 140 Looper Not accelerating

I had brought the carbs to a local OMC shop so I got the correct rebuild kit. They are the ones who checked the jets, and they are the ones who told me they were correct.

There is a screw that you can turn. Facing the block its to the top left of the carbs
 
Re: 1987 Evinrude 140 Looper Not accelerating

OK, look at the jets and post what numbers are where. Yes, adjusting the idle with the screw that advances and retards the timing is correct. Don't do it with the screw in the throttle arm on the side of the block.
 
Re: 1987 Evinrude 140 Looper Not accelerating

The jets are clearly visible after you take the cover away from in front of the carburetors !!----------------------Put a timing light on each cylinder ( one at a time ) and accelerate the boat ( on the water )----------------observe the light to see if you have steady spark to 5000 RPM.-------------Repeat this process and shine a STRONG flashlight into each carburetor bore and observe how fuel flows up the main nozzle.-------------Have you verified that the 6 seal rings are OK ( not joking here at all )
 
Re: 1987 Evinrude 140 Looper Not accelerating

How do verify if the sealing rings are OK?? I didn't see anything in the factory manual.
 
Re: 1987 Evinrude 140 Looper Not accelerating

Several ways.-------------Remove lower unit and remove spark plugs.-----------Put # 1 cylinder to just past TDC and push ( firmly ) on the piston.---You should hear a " ppooff " when the intake ports are opened---------------You remove intake manifold and reed valves.------------Use dental mirror and flashlight to inspect the block and rings.-----------------------Pour oil onto crankshaft and see if it leaks( rapidly ) to the cylinder below.
 
Re: 1987 Evinrude 140 Looper Not accelerating

I havent been able to get to the the numbers of the jets due to bad weather up north here..

I spoke to the previous owner of the motor and he said it ran perfectly last october when his yard took it off the boat (wanted to repower with a small motor) Considering the motor ran the same before carb rebuild, I am inclined to believe that the problem is not with the jets. I will get the numbers once the weather breaks..

If I had to guess its something electrical, that went bad, or is starting to go bad. Its not the power pack, that was already swapped out and tested.

any other ideas?
 
Re: 1987 Evinrude 140 Looper Not accelerating

I guess you could go on replacing expensive parts using the guess method , untill you happen to replace the offending part /s---------------I prefer testing and trouble shooting myself.
 
Re: 1987 Evinrude 140 Looper Not accelerating

OK guys. I finally got around to figuring out whats going on with the motor..I broke down and brought it to the mechanic. All that was wrong with it, was it needed some adjustments in the top mount throttle (which was new), and the cables on the motor end..Mechanic took it for a ride and said it was running top notch..He also, said once you put the throttle down, sit down and hold on cause that boat flies...

How about that?
 
UPDATE

I personally took the boat for a ride and though its 90 percent better its still lagging on acceleration.. The Mechanic verified that the Jets are the correct jets, he verified that the crank case is not leaking, he verified the timing is correct.

I can go from 1000rpms to 3000rpms no problem. At 3000 rpms the motor doesnt go, no instead of wating 7-8 seconds it takes 3 seconds for the motor to kick in and the boat takes off. At first I thought it was the prop slipping. The rpms would climb slowly, till the boat took off. I also notice that at 5000 rpms it creeps slowly up to 5500..

The prop I am using is a 14x19 long blade (apparently its a rare prop that has been discontinued). I just bought this moring a 13X19 prop alum. and I will attempt to put that on sometime within the next few days..

Anyone shed some light onto this situation??
 
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