1991 25hp evinrude starting issues

Joined
Nov 27, 2022
Messages
25
I am having an issue with 25hp evinrude to start and not die going up on throttle.

Compression 105 both cylinders
Leak down test less then 10 percent
New fuel tank and lines
Carb rebuilt with OEM kit
Good spark
New fuel pump
Have the cam roller set between both marks. Butterfly to the carb horizontal at full throttle.
Cam moves butterfly tight at the second mark.
Can’t figure it out
 

saltchuckmatt

Commander
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Jul 19, 2019
Messages
2,638
I am having an issue with 25hp evinrude to start and not die going up on throttle.

Compression 105 both cylinders
Leak down test less then 10 percent
New fuel tank and lines
Carb rebuilt with OEM kit
Good spark
New fuel pump
Have the cam roller set between both marks. Butterfly to the carb horizontal at full throttle.
Cam moves butterfly tight at the second mark.
Can’t figure it out
Define good spark.

Idle jet setting?
 
Joined
Nov 27, 2022
Messages
25
New plugs and wires and get spark touching against metal.
Ideal start at 1 1/2 turns out and slowly close tell it sneezes and back it of a quarter of a turn.
It just seeems like the timing is off
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,814
Does spark jump a gap of at least 3/8" or more , yes or no ?-----You have checked flywheel key ?
 

racerone

Supreme Mariner
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Dec 28, 2013
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So how did it start for you last season ?------What is your starting procedure ?-----Is throttle plate OPENING at the correct time and not too early ?
 

saltchuckmatt

Commander
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Jul 19, 2019
Messages
2,638
Have you looked at your primer system and is it working correctly? Not the primer ball.

Are you letting it warm up properly?

Maybe when it running, pull each spark plug wire off at a time and see if it dies.....
You might be having a problem with one cylinder or something.
 

909

Chief Petty Officer
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Jul 19, 2021
Messages
537
Rebuild your carb again and check your head gasket.
 
Joined
Nov 27, 2022
Messages
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Have you looked at your primer system and is it working correctly? Not the primer ball.

Are you letting it warm up properly?

Maybe when it running, pull each spark plug wire off at a time and see if it dies.....
You might be having a problem with one cylinder or something.
Primer system works good, I just saw a video where it says evinrude released a bill item saying to set throttle plate 1/4 to 1/2 past the two slots. I’m going to try this, this weekend. This would make since because it seemed like it was getting to much air
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,638
Primer system works good, I just saw a video where it says evinrude released a bill item saying to set throttle plate 1/4 to 1/2 past the two slots. I’m going to try this, this weekend. This would make since because it seemed like it was getting to much air
Yes, my 83 has that service bulletin but I figured by 91 it should have been fixed. Nothing to do with air really they just want the timing moved up before the carb starts to open.

Before doing that on mine it would run but hesitate before taking off.

Hope that works for you.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,814
Everything reported on this motor indicates that it should start right up and run like a charm.----So something / information is missing.----Are you holding the key in while cranking it over with the starter ?-----Battery fully charged and load tested ?
 

saltchuckmatt

Commander
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Jul 19, 2019
Messages
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So what is the current exact issue?

Will it start and idle fine? Put it in gear it dies? On the water or on muffs?

Describe in detail and post a YouTube video.
 
Joined
Nov 27, 2022
Messages
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So what is the current exact issue?

Will it start and idle fine? Put it in gear it dies? On the water or on muffs?

Describe in detail and post a YouTube video.
I will try to get a video tomorrow

I have it in an enclosed 55 gallon trash can. I have had it on ear muffs but the same issue.

I will set everything to what the book says to. I would line the cam roller up between the two marks but it won’t kick over. Then I would turn the throttle plate screw in a few turns where the cam roller is just past the second mark. It will then start, then I would adjust the idle speed screw starting at 1 1/2 turns then adjust it tell it sneezes then turn back a quarter of a turn.

Seems to be idle good put as soon at I go up on the throttle it starts to die. To me it’s seems that it’s not getting the right air to fuel mixture or the timing just doesn’t stay. I have messed with the air intake and fuel so many times.

But there is not much to timing on these things. It does seem to me that the throttle cam plate sticks, when I loosen the screw all the way out seems like it won’t move all the way back with it.

Hope this makes some since
 
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