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1973 25hp johnson -

H

hawaiian547

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Hello this is my first post.
I've got a 1973 aluma craft V bottom boat w/25hp johnson electric start, the boat has been garage kept for last ten yrs (not been used for last ten yrs) that I purchased in may this year I had it worked over before I took it out put new water pump cleaned carb. Boat ran really strong first 4 days on the water, all at once it has started to act up, it will run strong then bog down even with trottle wide open then kick back in and run strong again.
This last time we took it out it ran about 60% strong and still bogs down every so often. I have charged the battery, put new plugs in it, cleaned all the grounding points to the engine(sanded all the paint off).
I started it up in barrle of water and let it idle still seamed like it was boging down and then kicking back in and idling ok.
Any thoughts and advice will be great.....Thankx......:confused:
 
Could it be you are loosing spark on one cyl? Test for a short time in your barrel and if it acts up, then check for spark on each cyl. or see if one cyl becomes cooler than the other while it is acting up. I really think it is a simple solution.
 
i'll try that now if one cyl is colder than the other while its acting up what should I do at that point.....
My buddy at work says it sounds like a small air leak in one of the fuel lines, will that make it do the same thing?
To me it just sounds like I'm lossing spark while running....

ALOHA 4 THE TIP...........I'm fixin to try that.......
 
hello again , ok I looked over allfuel line connections and everything is ok.
I ran the motor in barrell at a low speed so water didn't get pushed out and it seemed to be running good , but after a few minutes it started to bog down and pep back up again....
I pulled the wire conecter off the top power pack while it was messing up and it didn't change a thing, I put it back on and pulled the lower one off and it killed the motor while messed up....
I reconected the wire to the power pack started the engine back up and put it forward gear again , started to run bad off the start so I pulled the spark plug off the top plug and it changed nothing, I put it back on and still no change to the way it was running ( bogged down) so I pulled the lower spark plug wire off the plug and it shocked me pretty DAMN GOOD the the engine cut off.... Does this mean I have a power pack going bad..... any thoughts .........I welcome all comments.......as this is my first boat and out board........ ALOHA.............
 
yes, it could be the coil for that cylinder, or it could be the point set that triggers that coil.

You can test the coil with an ohmmeter, or you can swap the coils top to bottom and see if the problem moves to the other cylinder.

If problem follows that coil - order a new one.

If it doesn't, you need to get a puller and remove the flywheel to inspect the points.

welcome to the 22CID world... nice little motors

34313_411104919365_566834365_4673443_1570033_n.jpg
 
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howz it (hystat) yes i will have to try swapping out the two coils from top to bottom.....
the engine closet in the pic. is a perfect match for my motor.......
my I contact you at a later date if the swap dosen't work..... I don't know anything about these engines and scared to dig in blind.....
I thank you for the info I feel like that should work but I will find out tommorrow.
If the swap does make the problem follow to the other cyl. then that means that coil is bad . Do you know how I can order a new one?

ALOHA TO ALL........MAHALOZ............
 
Great site right here to order parts. You might want to get a new water pump impeller too, it is cheap insurance to insure the life of your motor. It may still have the original impeller in it. Do you have any history on this motor?
 
you can find original service manuals and even technicians training guides on eBay for these motors. the original manuals are the way to go - excellent pics and easy to follow.

My 1975 in the back is identical too - just different hood graphics.
I also have a 1975 20HP Evinrude

a manual from any 1970-1976 18HP, 20HP or 25HP would be handy for you

shop.evinrude.com has all the original parts books on line and you can bring the part numbers back to the home page of this site and dump in the box that says[FONT=Verdana, Arial, Helvetica, sans-serif]

Enter OEM or Aftermarket
Part Numbers Only:[/FONT]
 
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Aloha once again \000/
(GUIDO2) when I bought the boat I had a small engine guy change out the impeller I bought a new one on line from this site, he said he was going to take off the carbs and clean them if needed to once he put the new impeller on and the water was flowing good, I talked to him earlier he said he never pulled them that they where fine and the boat has ran fine till now with this problem.
(HYSTAT) I will look in to getting a manual thankx for the tip on the site to go look for it....
I have yet to swap out the coils and see if the problem follows the one coil...I will leave a note on here on what happens once I do..... most likely tommorrow......


PS... I THANK EVERYONE FOR ALL THE ADVICE AND INFO!!!!!!!
I REALLY AM GLAD TO HAVE COME ACROSS THIS SITE........
ALOHA \000/ MAHALOZ......
 
hey guys I took off both coils that connect to the spark plugs and swapped them out to each other spot, the engine would not fire just turns over. I put them back the way they where and it started like always but still ran bad I once again unplugged the top plug wire from spark plug and it didn't change a thing...
Any advise as to what you feel is going on...
Is that top coil pack bad?

I looked at shop.evinrude.coms engine break down page and saw that they call these parts ( coil/lamination covers) .

this site has them in the parts catilog as (coil/ lamination ) & ( driver coil) whats the difference besides the price. I noticed that the connecters for the two coils have oppisite plugs to in sure they are on the correct wires to the engine.....
thankx and ALOHA .....A LQQK forward to hearing from you guys....
 
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I couldn't follow, but you need to swap the coils completely- you'll have to figure out how to overcome the connector gender. use a paper clip or alligator clip-whatever to make the connection. completely swap the coils so they are in each other's roles - both the small wire and the plug lead need to be reversed

assuming you did that and got the no start:
you want to compression test the cylinders. should be around 120-125 psi each

sounds like you have 2 problems on that motor.

when you swapped coils, the good coil got moved to a cylinder with a second problem.

You were running on 1 cylinder initially, now you are running on zero.
 
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yeah I switched the coils but couldn't connect the plugs do to the different end connecters, so I will re swap them out again and connect the wires some how. I have alligator clips.
I thank you guys for continuing to help me out and talking me thru this.......
I'll try that and let you know what happens.....
ALOHA \000/ MAHALO
 
ok !
I swapped the 2 coils out, made sure I swapped out the wires as well , the engine fired up and ran the same bad bogging and popping way.
I pulled the plug off the top spark plug the same thing it (didn't make a difference) put it back on and pulled bottom plug of its spark plug and the engine died.
I don't know much, but it sounds like the distributer if thats what its called on an outboard engine.
I am lost right now but willing to dig in to it with some advice and help...........
 
OK, you have successfully eliminated the coil as a possible problem

However it could be as simple as a bad spark plug. I don't know if you put new plugs, but always try that for the few bucks.

After that, you're down to 2 possibilities.

1. mechanical issue with top cylinder - low compression, bad reed valves - COMPRESSION TEST
2. points (requires flywheel puller to pull the flywheel and replace points and adjust point gap)

beyond that - there's some weird possibilities- like a weak permanent magnet in the flywheel, but that's rare
 
Thankx again (HYSTAT) yes I put new plugs as that was the only quick fix I new to try.
What do I need to check top cylinder for compression ? :confused:

Will a regular automotive pully puller work?:confused:
 
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