1988 Evinrude 140 Surging 4500 - 5500 RPM.

Chrisravosa36

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Ok, some may know that I have a 88 Evinrude/Johnson 140hp Looper, and had an issue with basically no power in the motor, it would go 4000rpm - 4500rpm and 27MPH, but no faster. I put 2 new fuel pumps in, this was a VRO motor but the P.O converted it into standard OMC pumps, one 2 prong pump, and then one three prong pump. I replaced both, I also rebuild the carbs. Both of which seemed to help today. I got on the lake, and started fine and easy, brought it out to the open, and opened it up and I got 3000RPM of non-planing speed. about 14mph. I put around for a bit, and I took off the cover to figure out what the heck was going on. I discovered in one of my attempts at taking off the cowling, I must have ripped a spark plug wire. #3 Cylinders tore out of the boot. So I put that on, started it back up and gave it WOT it had plenty of power than, I got up on a plane fine going about 30MPH or so and it started to cut off a bit, Im thinking that it was this wire that I stuck back in. Im going to get new wires anyways, but would this be the issue? It seemed to cut out down low as well, but it was most prominent at 4500- 5000rpm.


Any suggestions. I love this old motor and everything works great on i,t accept for this. + Ive gotten 6 people come over and talk to me about the Mako 17 and this motor, they are just one of a kind.

Here is a video of the motor and boat - https://www.youtube.com/watch?v=7xMkXmnBGWk&feature=share
 

Chrisravosa36

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i will take it out again saturday with new plug wires to see if this does anything.
 

jakedaawg

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The plug wires need to be carefully routed on these motors as they tend to ground out on the cowel latches.
 

Chrisravosa36

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The plug wires need to be carefully routed on these motors as they tend to ground out on the cowel latches.


ok, they should NOT touch the block either? What is a good solution for this? Zip Ties or the wire holding clamps?
 

jakedaawg

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Originally they used little bending metal clamps. These work if used and the loop in wire is a fixed to them in such a way that they do not ground on Cowell latches.
 

Chrisravosa36

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Originally they used little bending metal clamps. These work if used and the loop in wire is a fixed to them in such a way that they do not ground on Cowell latches.



this didnt work, im aiming it at the fuel water seperator, im going to take it off and try running it again. i belive this may be the issue.
 

Chrisravosa36

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1988 Evinrude 140 Surging AGAIN?

o.k Il gives some back history on the motor first, bought fall 2016, 1988 Evinrude (Johnson Decals) ran good, stayed cool. I take it on a test drive 2 weeks back, first time on the boat. It only runs to 4000RPM and 27MPH, this is what I did after that

*New carb rebuild kits and cleaned all carbs
*Two new fuel pumps (This motor runs off one standard OMC Fuel pump and a 3 prong pump OMC as well)
*took off fuel pressure valve (Attwood valve, when the tank expands on hot days, it lets the pressure out)
*It ran on 2 12 Gallon tanks that day, with a Y split, took the Y out and ran one tank.
*New Plugs

I then took it out again about a week ago, it ran 3000rpm and 14 MPH, opened up cowl to figure out why this is going on, I realized I broke a spark plug wire, put a new one in (just a little too short) and it ran better. I was getting passed 4000RPM and 27MPH. But then it hit me, The motor started to surge from 4500RPM to 5000RPM. And If I kept it WOT it would surge down to a fast idle speed. I thought on the lake this was a fuel demand issue. So I squeezed the crap out of the primer bulb and then ran it. It ran much better for 30 seconds, I did this a few more times. This is why I believe it is a fuel demand issue. I'm going to try running it without a fuel water sep. I think it may be that, because I have one of those clear bowl ones, and the whole bottom bowl just fills with gas every time, so I think there is something up with that.

Not sure what else this could be, I am almost certain the carb bowls are running dry at higher RPMS. When the motor is running, Should I have the gas tank vent opened or closed? Other than this the motor runs great. Am very pleased with the performance other than that. I have yet to get a top speed and WOT RPM out of this motor because of these issues.


Any help is great, thank you all

 

racerone

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I see no compression numbers posted.----Crankcase compression checked ?
 

Chrisravosa36

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I see no compression numbers posted.----Crankcase compression checked ?


i have not checked crank case pressure, but i have about 125 - 130lbs on each all in less than 5lb range. Also i did not notice this surging problem before when the motor only ran till 4000rpm. Only after the fuel pumps and carb rebuild this occured
 

Chrisravosa36

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I noticed one of the new fuel pumps that I bought is leaking. The bottom seal is leaking, whenever I squeezed the primer bulb it would squirt out the side of the pump. I also noticed the primer ball never really got hard. I ran it off one pump on the lake for a bit. and the ball was hard, no surging, but only 4000rpm again, So im guessing it was the pump.
 

Chrisravosa36

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Got the new pump. I had 4 people on the boat including myself. I got 4500RPM W.O.T. I tried taking the fuel water serp off, no difference. I tried with just me on it. No differences really. It took all three other passengers to get forward to get it to plane out. This is killing me because I know this motor should be screaming down the lake. Im guessing now that this is NOT a fuel issue. I need some help here :( Dont know whats next
 

Fed

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Your original VRO pump ran off a rubber tube for the pulse, your 2 prong pump doesn't seem to have a pulse connected to it?
2 prong pumps bolt to the engine to get their pulse, yours looks like it's hanging in the breeze.
 

jakedaawg

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It may actually be time to take a look at the vessel itself. If you had four people in and did 4500 rpm but then draopped them onshore and experienced no change it tells me that you have a waterlogged boat. This is very common. The foam in a 1980's vessel can easily be waterlogged adding many hundreds of pounds of weight. Aside from ripping out the floor and checking there is no way to know without getting it scaled and knowing the original dry weight.

It sounds like this vessel nevr ran well for you...someone sold it for a reason maybe?
 

Chrisravosa36

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Your original VRO pump ran off a rubber tube for the pulse, your 2 prong pump doesn't seem to have a pulse connected to it?
2 prong pumps bolt to the engine to get their pulse, yours looks like it's hanging in the breeze.

It does not look like it has a pulse line at all, both fuel pumps are held together on this bracket. Do you think I ought to just get a vro pump and put it back on but disable the oiling? What does the pulse do?
 

Chrisravosa36

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It may actually be time to take a look at the vessel itself. If you had four people in and did 4500 rpm but then draopped them onshore and experienced no change it tells me that you have a waterlogged boat. This is very common. The foam in a 1980's vessel can easily be waterlogged adding many hundreds of pounds of weight. Aside from ripping out the floor and checking there is no way to know without getting it scaled and knowing the original dry weight.

It sounds like this vessel nevr ran well for you...someone sold it for a reason maybe?


I dont remeber what trip it was, but when I had the problem with surging, I would squeez the primer ball alot than run it, I would get to about 35MPH and than I would start to surge again.
 

Fed

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Each fuel pump needs pressure pulses from the crankcase to make them work.
Your 3 prong pump gets that pressure from a rubber hose.
2 prong pumps will have a hole in the back that is supposed to bolt up to a matching hole in the block which provides to the pressure pulses.

Google Images.... 'Outboard fuel pump' and you will see the 2 different types.

If your 2 prong pump has no pulse connection it will not pump although it will still allow fuel through it albeit slightly restricted.

I'll have a little hunt today (early AM here) for the best method to send pulses to dual pumps, my guess would be to use two 3 prong pumps but maybe there's a better way using your existing 2 prong one.

Hopefully someone will chime in who has done it before, no sense reinventing the wheel.
 

Fed

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I just looked up a 1980 140 HP it it seems they only used one pump on them, possibly the duel pumps are for V6s.
The plot thickens. Maybe you only need one pump, that would sure make life easy.
Mod EDIT':. dead link removed

Anything racerone says will be correct.

Personally I'd remove the 2 prong pump & give it a try on one pump.
 
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racerone

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Can you folks not see that this is a custom set-up.-----Never had one in my hands.----I am sure the 3 prong pump is drilled to provide the pulse to the 2 prong pump.---That is why they are mounted the way they are with a gasket in between them.
 

Fed

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But he has fitted 2 new fuel pumps racerone and judging by his questions (no offence chris) there is no way did he drill out the new pump and seal it to the other one.
There seems to be a decent gap between the pumps perhaps chris can tell us but I'm betting they are stand alone otherwise chris would have already shot me down, will 2 pumps run ok off a single pulse line?
Just looking at the picture you'd need 2 gaskets & a metal spacer or 1 very thick gasket to make it work, nice & neat though.
chris will have all the answers as he fitted the new pumps, chris?

BTW racerone will his motor run ok on a single pump?
 
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