# Need help 40hp mercury



## Myblueinu (Mar 29, 2016)

New to the forums and boat motors. I have what I believe to be a 1995 mercury 40 classic, oil injection. Serial #0g238710. The guy I got it from removed the oil injection. He said just to mix it 50:1 and it will be fine. I guess that's right?? As I was looking at the motor I also noticed that since he removed the oil tank there seems to be no filter for the carb. Anyone know if I'm missing something, or if it is ok to run it that way, any help would be great.


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## sdm111 (Mar 29, 2016)

Yes mix is 50:1 and no there's no kind of air filter when u take the hood off you're looking straight into the 2 carbs throats. At least that's how all the ones including mine were no filer and no way to connect any


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## sdm111 (Mar 29, 2016)

Also if your mechanically inclined I'd change the impeller (water pump ) just for good measure. Whenever I get an outboard that's the first thing I do cheap insurance that its gonna pump water


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## Myblueinu (Mar 29, 2016)

Yea, I picked up an impeller and some spark plugs the other day. The guy at the store said is should change the oil in the foot too.

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## sdm111 (Mar 29, 2016)

Good advise


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## DaleH (Mar 30, 2016)

Myblueinu said:


> Yea, I picked up an impeller and some spark plugs the other day.


FWIW I have the same model in a 1997 year and I've been advised that the waterpump/impeller is the weakest point of this design. 

With a lot of use I'd plan on doing it every season to at least every other season. I boat in the salt, so since I may be in sandy waters I'll do it annually.

Oh and an 'air filter' in front of carbs is called the air silencer, that some call an air box.


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## onthewater102 (Mar 30, 2016)

https://www.repairsmanuals.com/mercury-outboard-factory-service-manual.html


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## lckstckn2smknbrls (Mar 30, 2016)

Most outboard motors don't have an air cleaner. When your out on the water there is not much dust so no need for a filter. There might have been what's called an air silencer.


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## Myblueinu (Mar 31, 2016)

Thanks for the info and the links, I should be taking it to a buddy of mine tomorrow who has some experience with outboard.

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## Myblueinu (Apr 5, 2016)

Well the motor runs, needs a water pump, I'm going to do that myself. Carbs need to be rebuilt as well, my buddy said he would do it for 350. That includes parts. I wish I knew what I was doing and could do it myself. Does that price sound reasonable? 

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## sdm111 (Apr 5, 2016)

Seems high to me there's not really much to rebuilding those carbs. If you can do the water pump you should be able to do the carbs


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## perchjerker (Apr 5, 2016)

for $350 (from a friend) he better be taking them off, rebuilding, installing , adjusting and making sure the motor is running properly.

seems high just to rebuild them if that's all he is doing


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## Myblueinu (Apr 5, 2016)

He said he would do that as well, guys kinda hard up right now, lost his job and is doing mostly side work, I don't mind helping him out, I just want to make sure I'm not getting raped either.

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## onthewater102 (Apr 5, 2016)

Rebuilding carbs is the easy part - it's tuning them in so they're in synch with one another that takes a degree of finesse. I'm assuming the 40hp being the same engine family as the 50hp and 60hp uses two carbs.

Actually, and I'm not certain what else would be different, but I have a 60hp parts motor with the larger carbs on it that i have no use for if they were something you can make use of. I don't know if I still have them listed on fleece-bay or not, I can't imagine they kept relisting since the end of the summer to now & i kinda forgot about them.


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## perchjerker (Apr 5, 2016)

well if you feel comfortable that he can do the job and do it right, then have him do it. I think you would probably may that if not more at a professional repair shop. I have never had anything done by a shop so I am not really sure what they would charge, you could always call one if you wanted to

and like you said, you would be helping a buddy out who needs a little

sounds like a win=win to me!


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## Myblueinu (Apr 5, 2016)

All true, I'm pretty confident in his abilities, before he fell on hard times he used to build strip boats and motors to race

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## JL8Jeff (Apr 5, 2016)

I think the carb rebuild kits sell for around $40-50 so figure in the time to take it all apart (is it 2 carbs or 3?), clean everything and reassemble with the new parts/gaskets and then reinstall and hook everything back up.


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## jy951 (Apr 5, 2016)

If this is the 4 cylinder 2 carb motor, it's very easy to work on the carbs. I can easily remove both carbs in 10 minutes. There is just one carb bolt that is slow to remove. I was wondering when you run that motor if you notice any fuel leaking down the throttle shaft shortly after shutting down.


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## Myblueinu (Apr 5, 2016)

Right now when running the bottom carb looks like a faucet lol. Don't know about the throttle shaft

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## jy951 (Apr 5, 2016)

I think those carbs will always drip some due to their design. The throttle plate shaft is verticle with a hole all the way through the top and bottom of the carb body. There is no oring or seal on this shaft. When the motor stops, any excess fuel finds its way through the hole and leaks out. I'm betting you will see dripping fuel of this shaft even when rebuilt. Most likely, this fuel just evaporates and you would not notice it. But since your oil tank is removed, it will be easy to see.


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## Myblueinu (Apr 18, 2016)

So I decided to do everything myself. Seemed to workout OK. Motor runs pretty well. Has good water pressure. Now I seem to have screwed my reverse gear somehow. It goes into forward and neutral fine. It will pick up reverse, but it pops alot and it just doesn't feel right on the throttle like forward does. I also can't seem to find the adjustment for it. The rod I can see down near the foot, just seems to spin, no up or down motion. Could someone please explain?View attachment 1
View attachment 2


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## perchjerker (Apr 18, 2016)

sounds like your clutch dog or reverse gear is worn out, or at least out of adjustment.

the clutch dogis a piece that rides on the prop shaft between forward and reverse gears. When you put it in forward the dog slides one way and engages the gear with tabs on the dog. Go into reverse it slides the other way to engage reverse. There are tabs on both sides of the dog and on the inside of forward and reverse gear.

You know how When you go from neutral into gear, if you don't do it with a firm smart shift you hear a ratcheting noise? That's the clutch dog slipping on the gear and wearing it down like a tooth. 

After a while these edges get rounded and it just cant hold under load.

there may be a linkage adjustment, or it just might be worn out


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## jy951 (Apr 18, 2016)

There should be some adjustment on the end of your cables. You might try removing the cable and putting it into reverse by hand and see if that works.


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