140hp Evinrude dies at WOT

Jmitch1102

Seaman
Joined
Nov 26, 2017
Messages
74
I just bought a 89. 140hp Evinrude. I just installed it in my 1990 sea nymph. I dony know much history of the motor. I checked the compression before o bought it. All the cylinders were around 120-125. I took the boat out today. It started right up and idled fine. When I would give it full throttle it would begin to accelerate. Then it would start to cut out. Sometimes it would even die. I put new fuel lines and fuel filters. Also a new fuel water separator. I disconnected the VRO. My tank is already mixed from my previous motor. I?m going to check the new fuel lines for leaks. I tried squeezing the ball while accelerating. It did not help. Anyone have any suggestions?
 

Joe Reeves

Supreme Mariner
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Feb 24, 2002
Messages
13,262
Carefully clean the high speed jets (4) with a piece of single strand steel wire.... located behind the float chamber drain screws.
 

Jmitch1102

Seaman
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Nov 26, 2017
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I pulled one earlier and checked it. It was clear. I wil pull the others and let you know thanks!
 

racerone

Supreme Mariner
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Dec 28, 2013
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Check for spark on all 4 leads and check the flywheel key , timing may be off.
 

Jmitch1102

Seaman
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Nov 26, 2017
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I checked spark on all 4. I did have spark. I do have a new set of plugs to put in. I was waiting until after I ran deep creep through it. I live 45 min from any launch so I’m trying to eliminate as many things as possible before I try again. I was told the motor ran fine but the guy only had the boat out one time. He wrecked the boat on his first trip out. So upon buying the motor I could not test drive it.
 

jimmbo

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May 24, 2004
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12,944
I suspect dirt/crud in the fuel passages downstream of the main jets. Of course that means removal of the carb, a thorough cleaning, reinstall and link and sync
 

Joe Reeves

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Feb 24, 2002
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Mitch..... The most common things that will cause a engine to hesitate, stall, die out, when throttle is applied is:

1 - Clogged high speed jets.
2 - The throttle butterflies opening too soon in relation to the timing.
Butterflies should just start to open when the scribe mark on the cam is dead center with the center of the throttle roller. Not before or after.
3 - The timer base under the flywheel sticking as the throttle is applied.

I understand your problem as having the engine bog down as throttle is applied.... is that the case?

Also, the 1989 140hp model is a "Looper".... the carburetor face plate "with" the thick sealing gasket must be in place when running, otherwise the engine will run lean and die out when throttle is applied (usually).
 

Jmitch1102

Seaman
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Nov 26, 2017
Messages
74
Yes it accelerate for the first couple seconds then it dies off. If I throttle back I can keep it running. If I leave it at full throttle it will completely shut off. It starts right back up.i put some deep creep in it and planned on running some through the carbs once I was in the water. I did leave the ?air box? off during the test run so I could access the carbs. Would this need to be on for the engine to run at high RPM? I?m not familiar with a ?looper?. What does that mean?


Mitch..... The most common things that will cause a engine to hesitate, stall, die out, when throttle is applied is:

1 - Clogged high speed jets.
2 - The throttle butterflies opening too soon in relation to the timing.
Butterflies should just start to open when the scribe mark on the cam is dead center with the center of the throttle roller. Not before or after.
3 - The timer base under the flywheel sticking as the throttle is applied.

I understand your problem as having the engine bog down as throttle is applied.... is that the case?

Also, the 1989 140hp model is a "Looper".... the carburetor face plate "with" the thick sealing gasket must be in place when running, otherwise the engine will run lean and die out when throttle is applied (usually).
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
"Looper" is a loop charge design rather than the older crossflow. More efficient. I'd look at the fuel pump if it falls down after coming to speed. Try pumping the primer bulb when it's faltering
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Yes it accelerate for the first couple seconds then it dies off. If I throttle back I can keep it running. If I leave it at full throttle it will completely shut off. It starts right back up.i put some deep creep in it and planned on running some through the carbs once I was in the water. I did leave the “air box” off during the test run so I could access the carbs. Would this need to be on for the engine to run at high RPM? I’m not familiar with a “looper”. What does that mean?

Okay... Check the other two things that I mentioned. Yes, the face plate and gasket must be installed for the engine to function properly.

The looper got its name due to the manner in which the fuel is delivered and circulated within the cylinder combustion chamber... it actually enters and heads upwards for the other side of the cylinder, makes a loop and heads downward towards the exhaust ports on the other side. Easy to spot as the powerhead has no intake port side-plates whereas the cross-flow model does... the removal of the side-plate on the cross-flow allows one to view the sides of the piston.

Also the cross-flow incorporates metal dual barrel carburetors... one carburetor for every two cylinders (V4, V6, V8). The looper has one plastic type carburetor for each cylinder and is much more fuel efficient due to many improvements over the cross-flow.
 

Jmitch1102

Seaman
Joined
Nov 26, 2017
Messages
74
I put the throttle in WOT and wiggle the timing base. It moved free. I haven?t looked at the butterflies yet. I?m wondering if my issues weren?t just from me testing it with the carb cover off? I also need to adjust the throttle linkage. It is stiff going into reverse and neutral takes a little playing to get it into. Thanks everyone for your help.
 
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