"72" 125 hp johnson

[icy]

hello all.. I have a 1972 125 hp johnson that has 75 lbs compression in 1 cyl.. from what I can gather reading forums, it sounds like a ring.. My local machanic is tellimg me that this motor isnt worth rebuilding because lower end parts are no longer available.. my question is, is it really not worth rebuilding and is it something that i could do myself if it is.. I have rebuilt motors before, just not boat motors.. what would be a good book to get if its worth building.. at this time the lower end sounds and functions fine.. Boating season is coming fast and i need to do something so that im ready for it when it gets here!!!

 

[Saskatoon2005]

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icy,

If you have rebuilt motors before than this should be pretty easy...I'll tell you what, if you upload a picture of your motor (without the cowling on it), from all four sides, I have a manual and should be able to help you do the job.!

 

[Saskatoon2005]

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icy,

Is it a V4? i am just looking through my manual. Trying to figure out which model your is. 125Hp 1972....Hmmmmm.

 

[icy]

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yes i believe it is.. i dont have the model no avalable to me right now, but i could get it if needed maybe tomorrow..

 

[Saskatoon2005]

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No that is fine, do you know if it had 4 spark plugs? LOL that means it was a 4 cylinder and that means a V-4...LOL! Well, I imagine it has to be....let me set up the notes you will need and then I will upload them.....

 

[Saskatoon2005]

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Sorry,

My batteries just went dead...as long as you are not in any hurry, I will try and get them uploaded tonight or first thing tomorrow! LOL! Sorry!

Patrick

 

[icy]

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no hurry as we are in the middle of a blizzard right now anyway.. it will likely be saterday or sunday before i get a chance to look at it.. my biggest worry will be getting parts from a reliable dealer.

thanks
Corey

 

[emdsapmgr]

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Check out this 72 powerhead for sale on ebay: 230099007598. If that powerhead is sound, just bolt your 125 heads, carbs on the block.

 

[tashasdaddy]

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i'd jump all over that power head, $200 w shipping. looks clean. ask him if it ever ran hot. change the thermostat before installing. here a good thread that explains your lower unit,

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=28;gtid=1100925

 

[F_R]

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The lower unit is the Hydro-Electric type. (how obsolete? Very good units if you keep the seals not leaking and change the oil once in awhile. Takes BRP Premium Blend oil. It can last a long time if not neglected.

And yes it is a V4

 

[icy]

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by bolting on my heads and carbs on this one, does that make it the equivalent of a 125?? this sounds like an easy deal right now, but i would like to have the 125 hp..

 

[emdsapmgr]

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It is likely that the 125 block has somewhat higher porting than the 100, so you will not wind up with 125. However, the upside is that the 100 is a low port engine that makes more torque at low rpm. Add your heads and carbs and you will have a great pulling engine. Bottom line: you will notice little top end difference after the changeover.

 

[tashasdaddy]

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you can go here and compare different parts, Brp site is down. why i'm directing you here.

http://www.ishopmarine.com/ishop/js...CatFilter=BMC&eCatSupFldr=supplier-100-005-EJ

 

[tashasdaddy]

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before you do anything read this: you may get a $10 fix

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=28;gtid=1268953

unning it in the fuel is more of a preventative. you can warm the engine up on muffs, and spray into carb. this is a higher concentration than running in gas. spray it in to where it almost stalls, this is what breaks up the crud in the engine (it's gonna smoke like it's burning up) keep doing it until to smoke lightens up. then running it the gas will help clean the carb, but if the carb is really varnished up, the only help is a disassembly, soaking, and a rebuiled kit. there is nothing in seafoam that will hurt your engine. NEVER use starting fluid on a 2 stroke engine.

 

[quilter]

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Have you pulled the head and find out what the problem is? could be a head gasket problem or broken ring. If broken ring it could have a bad head also. when changeing the lower unit be sure you use the right electric shift oil.

 

[icy]

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Ok i have another question. what is that 100 hp powerhead worth vs rebuilding mine? this guy says that it has never been hot that they can tell. I don't want to spend more than what it would cost me to rebuild mine. if i rebuild mine then i know exactly what i have vs buying the other powerhead.. I also know that simply replacing the powerhead would be "easier" than rebuilding. So I guess my question is what would be a good max bid (including shipping of $87.05)?

 

[tschamp20]

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depends,that is a great looking powerhead.if i had to have it i would be willing to pay $700.maybe
always have to wonder if it really runs though. thats the great risk w/ ebay.whats gonns happen to them a negative feedback?! good luck.i got a lower unit from ebay,paid $300 still works great.that is a nice lookin powerhead though

 

[Saskatoon2005]

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If you can rebuild yours...THEN I WOULD DO IT! As long as you don't have to worry about downtime. You don't use your motor to make a living? Then take the time and rebuild it. Buy a good manual and do it right the first time.

Then install a water pressure gauge, and a temperature gauge, these two tools work great together to make sure you don't have costly repairs later on. They will keep you in good knowledge of your impeller...Good Luck!

Patrick

 

[mikesea]

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pull that side head off asap,often a broken ring is obvious by nicking up the piston and head,or the head gasket might show obvious also,

 

[icy]

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ok.. il start by taking my OWN compression readings and go from there.. If i remember correctly from last summer, the mechanic told me that there were 3 cyl @ 120something lbs and 1 @ 70 lbs.. but i cant remember what cyl it was anyway.. i have a compression tester from building small block chevys, for the dragstrip, so ill take some readings and go from there.. if/when i find out what cyl is low ill take off the head and take a look see ill post the results here..