Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

jonnymarquis

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I did indeed buy my first boat, it is a 1975 marquis 17' with from what i have learned a 1972 125Hp (model 125283R) evinrude OB motor. my question is that what mix i should use and at what ratio. the guy i bout it from didn't sound to sure on what to use or ratio. also does anyone know where i can get any info on this motor online. and maybe any other tips or tricks that may help me, remember im a new boat owner, Thanks in advance to all.
 

mitchell6

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Re: Ok guys and gals can you assist me, motor question?

Re: Ok guys and gals can you assist me, motor question?

50-1 on your ratio
 

jay_merrill

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

You can go to www.shop.evinrude.com to get info on parts. Each section has not only a parts listing, but a "parts explosion" (diagram), as well.

Your motor has hydro-electric shift, so I recommend doing a search on hydro-lectric shift related items, here at iboats. You will learn a lot of important info, by doing so.



???
 

Texasmark

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

I had a '72 125 Johnny. Very very good engine. Very quiet, pretty good on fuel considering it's predecessors, and purred like a kitten. Had it on an 18' Caravelle tri-hull and believe it or not, at a company picnic one Saturday was able to get 5 skiers up and keep them up for a couple hundred yards with the same prop I used for everyday boating.

Mark
 

tashasdaddy

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

be aware, that you only use Type C Premium Blend gear oil. you have a Hydro-electric shifft lower unit.

from (J. Reeves)

The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.

You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)

Note: The engine must be running OR have the driveshaft turning by some other means in order for the engine to shift.

In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)

To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.

This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.
 

Texasmark

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

Tas, any comments on why OMC went to that in the first place? You probably know the reason they dumped the idea too. I have an idea as to why. As I recall I really liked the smoothness and firm engagement that I got with mine......never had a problem with it in 5 or so years.

Thanks,

Mark
 

jonnymarquis

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

ty gents so far you have been very informative and i really appreciate that, i will soon be taking it on the water to see how she runs around the dock. if there are any problems that should arise I'm sure you people can talk me through them, ty again, keep the info coming. and mark glad to here that that motor is a good one, i was guessing that $300 wasn't a bad deal for the package. and some fixing up the interior is in the works just wanna check the mechanical first.
 

ezmobee

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

If I were you, before I took her out, I'd replace the water pump impeller and change the lower unit oil (make sure to use the correct oil that TD indicated above). Make sure to replace the gaskets for the lower unit drain and vent screws when you do this. They are single use items.
 

jonnymarquis

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

where can i find these parts? and how much water is a good amount to know that it is getting enough?
 

ezmobee

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

The issue with the water pump is it's a rubber impeller. It could have become brittle over time. It could break up while you're out there and chunks of it end up in your cooling system. Some recommend replacing them every 2 years. I don't do mine that often. However, if you don't know when it was last replaced, I'd definitely replace it.

http://www.iboats.com/mall/partfind...d_poid=109117&gd_row=101&**********=778298591
 

F_R

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

The issue with the water pump is it's a rubber impeller. It could have become brittle over time. It could break up while you're out there and chunks of it end up in your cooling system. Some recommend replacing them every 2 years. I don't do mine that often. However, if you don't know when it was last replaced, I'd definitely replace it.

http://www.iboats.com/mall/partfind...d_poid=109117&gd_row=101&**********=778298591

We had a LOT of trouble with instant failure of those water pumps. And a LOT of burned up powerheads because you can't shut it off fast enough when the pump suddenly fails. The hot light/horn doesn't even have time enough to go off. My suggestion is that you take it apart and see what kind of pump it has in there. If the original aluminum housing, I reccommend that you replace the whole pump kit, not just the impeller. The aluminum housing is no longer made and is replaced by a 378416 water pump repair kit which has a plastic housing with stainless steel liners. A much better pump. Once you have the new plastic housing, normally no need to replace it in the future--only the impeller.

OK, so the kit is about $100. Whatever you want to do is ok with me.
 

tashasdaddy

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

i was in Viet Nam when they did that. so they did not cousult me. new technology at that time, it worked great then, but mechanical worked better, less failure.
 

jonnymarquis

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

OK put the gas tank on and cranked her up just to see if it would run, after getting fuel in her and holding down choke she fired very slowly at first then finally it ran BUT i can only keep it running buy every 5 seconds or so choke it to keep it going hold that for 3 - 5 seconds then release, then wash and repeat. what can be wrong?
 

tashasdaddy

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

sounds like carbs are dirty, also replace all fuel lines carb to tanks, with alcohol resistant lines, ethanol. read the TOP SECRET FILE.
 

jonnymarquis

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

ok so where is the best place to buy a repair manual for my motor?
 

jonnymarquis

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Re: Ok guys and gals can you assist me, motor question? 1972 125hp evinrude.

OK i have been shopping on iboat and have put three thing in my cart the repair manual, Water Pump Impeller (because that was all i could find, cant find the hole repair kit) and Carburetor Kit, for when i take out the carb and clean it, so is there anything else i can get to help out get this thing ready for the summer of fun?
 
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