Flywheel Torque ? 1971 25HP Evinrude

[Coosa River]

Hey Folks

I've been doing some lurking around here the last few days......finally got the urge to join, as I can see I need more answers. Great forum BTW....lots learned already.

I'm located in Central Alabama (close to the Coosa River). I bought an old Fisher Marine flat bottom last week with a 1971 25HP Evinrude on it.....(model 25103S). I also got a repair manual, but am getting conflicting answers on the flywheel torque. Can you help me with the right answer ?

I'm sure I'll be back to ask more questions. This old motor has seen a lot of water I'm afraid......but am willing to try to work with it for the time being. Fingers crossed, with cell phone in pocket on every trip.

Thanks in advance,

Coosa River

 

[steelespike]

Re: Flywheel Torque ? 1971 25HP Evinrude

Welcome, My 89 after market ser.manual says motors prior to 77; 40 - 45 ft lbs. bore and crank clean and dry.

 

[jasper60103]

Re: Flywheel Torque ? 1971 25HP Evinrude

Welcome aboard. There's a lot of helpful folks and info available on this forum.

That's a light weight 25, and I hope you get her going. She should push that flat bottom well.

 

[bhughes]

Re: Flywheel Torque ? 1971 25HP Evinrude

I've got a '74 25hp I've had a few months. Once I replaced some old fuel lines and cleaned the carb really well it has been running perfect for me. Really pushes my 14' skiff down the water. Best $300 I ever spent.

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

Thanks....that's what I kept coming to, but was being told something different from a local. I actually sheared the key after a backfire from having the points set incorrectly, and carb all out of whack. It appears that most of that has been corrected now. I will try it at about 45 lb torque.....maybe it won't shear another key since the backfiring is gone.

This motor fits this 15 ft flat bottom very well......just hope I can get the rest of the hard headedness out of this motor......then again, I should be used to that by now with "things" around here.....I raise goats as a hobby.



Coosa R.

 

[14ftgrumman]

Re: Flywheel Torque ? 1971 25HP Evinrude

You do What with goats?

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

I raise/milk a couple of dairy goats....Alpines. Got chickens for eggs/small garden too. It's one of those country boy/living off the land a little cleaner type things. I'm attempting to add a couple a Spotted Bass to my diet also.


OK, I took the boat to the river yesterday. The 25 cranked easy, and idled very smooth. Put it in forward and started up the river.....got to about 30% throttle up, and the motor developed a cough/single miss. Under about 30% the motor ran smooth....above that, it would have the single cough about every 5 seconds or so. Increase the throttle, and the cough frequency would increase also....maybe 2 to 3 seconds apart. The motor seems to be firing fine between these coughs. This cough is very much like a cough that you would hear at idle with the low speed needle set too lean.....but like I said, this thing runs near perfect at low throttle/idle.
I little history. I've replaced (new) both plug wires, plugs, points, coils, condensers,.....cleaned out carb, installed new float/needle....replaced fuel line from tank, and installed new fuel pump. I replaced the crankshaft seal on top. Gas tank air valve was fully open.
When I had the carb off last week, I looked at the reeds.....didn't see anything that looked bad from that glance. I only soaked the carb in cleaner, and blew it out good with air. I did not pull the fixed high speed fixed jet, but am thinking that I might should have now.

Like I said, this "miss" frequency happens with throttle increase. I'm just a little bit stumped now......don't know if I should be looking for fuel or electrical problem now.
This cough is the reason the seller sold me this boat/motor, and he told me about this before I bought it. He was a bit of a shade tree mechanic like me, and he had give up on this one. I'm determined to find this bug.....just no good reason why this little boat and motor can't take me fishing.....I don't want to give up yet, but also don't want to keep dumping money into this old of a motor.

Thanks for any suggestions, as I'm a bit out of a direction to look now.

BTW- I did put a couple of Spot's in the boat....have plans for them tonight at supper, so the trip wasn't a total bust.

Coosa River

 

[bktheking]

Re: Flywheel Torque ? 1971 25HP Evinrude

I think you may have answered you own question. If you are going to clean and service a carb do it completely, cutting corners especially with the knowledge from the PO that it was doing this leads me to believe that the high speed circuit/jet still needs cleaning. Re and re, clean it and try it. It sounds like it's running lean.

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

So you're thinking fuel problem.

Do you recon I would be able to see damage/problems/wear to this jet.....or would it just be better to replace it with a new one ? Is there anything else that I can look for while I have the carb off again ?....any tiny ports that I might be over looking ?

Thanks,

Coosa River

 

[bktheking]

Re: Flywheel Torque ? 1971 25HP Evinrude

You might, remove and inspect. Typically they will have gunk inside them , I use a toothpic to clean them out with a some carb spray, wood won't damage anything. The tiny ports are usually associated with idle but you said it idles well so I doubt that it.

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

OK......will take carb back off sometime today/pull high speed jet this time. Yep...you couldn't ask for one to run much better at low or trolling speed....it's that throttle up where the skip/single cough sets in. Also, I had tightened the armature plate up like was suggested on this forum in other post.....so I think I've eliminated any wobble there that might be causing the problem.
You guys are great.....I've been in maintenance most of my life...not outboard motors though. I usually can detect when I'm talking with folks who have been there and done that already. It sure helps a lot when someone can send you in another direction to look at....so thanks again for keeping this forum going.

Coosa River

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

Well, went through as much of this carb as possible. The high speed jet in the bottom had a stain about it, but nothing gumming it up. All the ports seen were blown with carb cleaner/high pressure air again......nothing seen to clog it.

I did notice the small round gasket that sets in the middle of the bowl, separating the lower bowl from the upper carb was a bit dry rotten looking. I smeared a skim of RVT on both sides of it before putting the carb back together......also smeared a little RVT on the other gaskets as well.

There is just no way that I can check for this problem in a barrel.....will have to take it back to the river when I get time. If it looks like that I made any change in its condition, then I will probably order a carb kit for it....may need to anyway. I'm sure I'll be back with more questions.

Coosa River

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

Results of my efforts were not good.....I can't get it to even crank now. A few sputters and coughs is all. Lots of smoke coming out of the exhaust while it is trying to crank......not sure what has went wrong now, as I really made no adjustment changes that would effect it this bad.

Scratching head,

Coosa River

 

[Dhadley]

Re: Flywheel Torque ? 1971 25HP Evinrude

That small round gasket around the tube is critical. Take the carb apart and get rid of all the RTV. It may be all thru the carb now. Then get an OE kit and replace the gaskets with no sealer.

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

Yep....I kinda wondered if I wasn't doing the wrong thing with the RVT. I was thinking I might stop some false something coming from somewhere.....and was hoping that I would make a change in operation to let me know that I was at least meddling around in the right area.......didn't really think that I would make a change that went this bad.

Question.......does iboats parts carry this carb rebuilt kit ? and which one do I need.....please put link to it if possible. Motor model 25103S.

Thanks,

Coosa River

 

[steelespike]

Re: Flywheel Torque ? 1971 25HP Evinrude

Don't be afraid to look for parts yourself. I found the kit in less than 30 seconds with very little computer savy, I can't even post a link; part number is 18-7042 same for 20,25,28 and perhaps others.Just use the tabs at the top of the page.

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

OK....I've been there, but am confused. They show 4 different carb kits (one out of stock).

The numbers Evinrude # listed there does not match any numbers I'm showing here on my carb, or motor.

There is an "M" on my carb.....I'm assuming that stands for Mallory.

There are numbers stamped in my carb 313355 ....and I think a "c"

There is an ink number on my carb also .....38453 and a 6 ?, or last number maybe an 8.....kinda hard to read.

I'm not sure if the pics of these kits are accurate, but I do see in the pics that there is a gasket (the one that has more "body" in the center part.....a little smaller than the perimeter bowl gasket) .....this gasket is either missing from my carb now, or either does not go with this particular carb.....can you explain, as I really can't see where this gasket fits this one here.

I can see in the pics where many of the other parts would fit.

Please Help before I make my order......I for sure want to get the right kit if possible.

Coosa River

 

[Coosa River]

Re: Flywheel Torque ? 1971 25HP Evinrude

Even though this carb fits the motor.....I'm beginning to wonder now if this is even the right carb for this motor......maybe the basis for all my trouble if it's not even the right one to begin with.

Coosa River