1970 evinrude 25 hp Q's

BF

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Hiya,<br /><br />Tomorrow I'm gonna go look at a 1970 evinrude 25 hp tiller with electric start (model 2500C). Hasn't been used in about 3 years. Owner bought it as a backup motor about 15 years and says it has worked well when he has used it (which was not often). He bought it from the original owners (old couple with cottage on the same lake) and says when he bought it, it was showroom condition with very low hours, now it has a few more scratches, but not many more hours of use on it. Has tank & hose & spare prop.<br /><br />I intend to do the usual things (check LU oil, compression, spark, and see it run in a barrel), but is there anything else in particular I you can tell me about this model? If I buy it, I'll replace points/condenser, plugs & water pump. Unless it runs surprisingly well, I'll also do a carb rebuild. I'll try to remember to look over the coils to see if they're cracked. Anything else I should watch for?<br /><br />Do these guys have thermostat's in them? A poster here (Paul) told me that earlier 60's versions didn't and idled poorly as a result, curious if this would be the same.<br /><br />How much change was there in this model between 1970 and 1971? The '71's have the squarish cowling style that continued through the 70's, but is the engine also fundamentally different?<br /><br />Anyway, it'd be nice to have something a bit bigger on my 16' aluminum (has 80's 15 hp 'rude on it now), and if there is life left in this 25 after doing the maintenance, it could work out. Price is right, and electric start would be a treat (esp. for wifey).<br /><br />Thanks for your $02.<br /><br />Brent
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

Hello BF.<br /><br />The 25's had a thermostat. The only engines larger than 4hp OMC sold that didn't (past '57) is the 28hp and the 33hp. <br />The '70-'71 25hp used the same magneto system used since the '50s into the late '80s. If the ignition coils are original, they are good candidates for having cracks. Unfortunetly, you can't examine them without pulling the flywheel. If you really want to check, the flywheel nut torque is 480-540 in/lbs. You can replace everything under the flywheel (coils, points, condensors) for appx. $70 CDN, if you order parts from the 'States.<br /><br />I don't know much about the differences between '70 and '71, other than the obvious styling changes. Hopefully someone else can fill you in on this.
 

BF

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Re: 1970 evinrude 25 hp Q's

Paul... you da man. thanks.<br /><br />Do they have a charging coil under the flywheel too? Or are these guys just battery drainers?<br /><br />thanks again,<br /><br />Brent
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

They just drain the battery. :) <br /><br />Seriously, since there's no constant load on the battery, it lasts a long, long time.<br />There's no optional generator listed for the 25hp either.
 

Bass Runner

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Re: 1970 evinrude 25 hp Q's

Wierd i have a gen. on my 1968 evenrude 33hp, but you don't have to worry about it running the battery down it will last a long time unless you are running a lot of lights all the time. I had a 85hp jet on a 16' wide beam boat, lots of power and shallow draft what else does a guy want? :D
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

Bass Runner - the 25hp uses the 22.0 CID block, same as the 15-18-20hp. Not like our 25('50s)-30-28, 35-33 ,40hps (35.7, 40.5 and 43.9CID blocks respectively). <br />There's no bolt on generator for the 22.0CIDs.
 

BF

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Re: 1970 evinrude 25 hp Q's

So, how were the "small block" 25's? They weren't notoriously wimpy were they?? Did they really perform like a 25 hp, or more like an 18 hp? Was the bump up to 25 hp done by carb/timing? <br /><br />I haven't closed the deal (yet), but would be using this motor on a 16' aluminum (with an '82 15 hp on it now). I'd expect there should be a pretty good performance jump from my 15 hp to a 25, even if it's the small block variety (?)... or do you think the difference might be subtle? I'm not sure what the displacement of my 15 hp is... maybe that'd be a better comparision than the hp rating?<br /><br />I saw the engine on Sat, overall it is in VERY good condition (compression 130+ on both), runs good (a queen of the boathouse). The only reason it didn't come home with me was there was a problem with the electric start. A couple years ago the electric start bracket broke off the block... they took it in, but when they re-installed it (new studs, some light welding on block to repair mounting locations) they didn't align it well enough. Now the starter gear is too far away from the flywheel to engage it. The current owner wants to take it in to a machinist he knows to get it fixed (not the one that botched it)... I thought about just taking as it sat (for less $$) but given that he knew someone and acknowledged the electric start is useless now and he was adamant that it should be fixed (was p/o'd that he hadn't noticed it after the repair had been done - he hadn't used the electric start since then). We left it with me calling him in a couple days to see where it's at....<br /><br />I did notice that there was an empty mounting hole on the rear starboard side of the block (starter is on front port)... Anyone know what this was for? If it's an alternate mounting location for the starter, then it's problem solved!<br /><br />thanks,<br />Brent<br />anyway... so what about
 

Chinewalker

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Re: 1970 evinrude 25 hp Q's

Hi BF,<br /> The 22-cube OMC block had a long run from 1957 to about 1976 or so. Even as a 25hp it made good power, although it was a better speedster than a puller (as a 25hp). The 31 cuber that replaced it had more lugging ability. The 22 cube 25 liked to rev to make the ponies. It gained them over the 18 by carb and intake changes. I'm not sure if there were porting changes, too, but there may have been. Prop it to run between 5500 and 600 revs on your hull...<br />- Scott
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

Here's an interesting little conversation that came up here recently regarding the 22.0CID engine's performance: Carb Mods.
 

BF

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Re: 1970 evinrude 25 hp Q's

well, it's mine now! given that I couldn't find a pict of what a 1970 25 hp "sportster" looked like when I was trying, I'll try and post a pict of it here...<br /><br />What's the standard pitch prop for these guys? I think it's got a 9x9 (?) on it now. I also got a 9 1/4 x 11 along with it (that pitch sounds more correct to me).<br /><br />Is the seloc manual covering these motors OK?<br /><br />Thanks,<br /><br />Brent<br /><br />
25hp_evinrude.jpg
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

Sweet!<br />9x10 was standard. 9x9 was an option.<br />That doesn't look like the 9x10 weedless that suposedly was standard. They're kind of corkscrew shaped.<br /> 1970 Johnson spec sheet. <br />(Same as evinrudes of course.)<br /><br />I've got the Seloc manual that covers that engine. It's '56-70 under 40hps. It's not bad, especially compared to the clymers for those years at the library. Factory manual is best: check out ebay.<br /> '70 25hp 'rude manual (read the text)<br />Ya got 1 day to snatch that puppy (be certain it's the repair manual not the parts manual)!
 

BF

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Re: 1970 evinrude 25 hp Q's

thanks for the info (again) Paul. No it's not a weedless prop on it. I'd be surprised if weedless was the standard prop on motors of this size. On the brochure, the thing beside weedless prop denotes "prop can be selected at time of purchase" or something along those lines (I think). Thanks for pointing out the manual... looks like something I should own!<br /><br />The kill switch has come apart, and the starter switch works OK, but the rubber cover is cracked (looks to be the same kinda switch as the kill)... do you know of a source of these? My guess is there should be some kind of generic push button rubber coated switch that fits many years/models/makes (?).<br /><br />Thanks again!!<br /><br />Brent
 

Paul Moir

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Re: 1970 evinrude 25 hp Q's

I misread that footnote about the props. It seemed weird to me that the weedless would be standard on a 18hp...<br /><br />I've actually seen switches like those I think in the auto section of Canadian Tire. About a 5/8" diameter chrome plated push button. They don't have the rubber tops for them though. You'll notice you can just pull the rubber cap off.<br />Normally, I get that sort of thing at the local outboard junkyard. I'm fortunate to live about 20 minutes away from one. See if you can find one around - it's the best place for parts.<br />But I expect you can find that switch at any marine parts place. It's super-generic.<br /> Check this out.
 
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