Question about Evinrude Carb compatibility?

[MDCrappie]

Johny25 » Sun Jan 26, 2014 3:44 am[/url]"]I see what you are trying to say MDcrappie but believe me both those blocks are the exact same and came front the same cast, cylinder heads too. There is nothing different internally on them at all. Just look........they put different numbers on replacement parts but they are the same and match the 25hp
https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1982&hp=35&model=E35ELCND&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase

Not trying to say, I'm say - I would do some more research to be 100% sure they are the same, and putting out likely $200 plus.

How sure are you? Willing to pay back all the OP money he puts out if it doesn't work for him?

Here are the 1982 25hp "replacement" parts, and I don't see where they match the 35hp. (in the link you provided)
https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1982&hp=25&model=E25CNE&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase
0394995 = 0394994?
0396165 = 0396194?
0433534 = 0432540?
0435943 = 0433533?
0484784 = 0435942?
L/P 2296.64 = L/P 1339.99?

Each of the "discontinued" parts is shown with a "replacement" number and they are different in the 25 and the 35. Why?


BTW - have YOU ever put a 1982 35hp carb on a 1982 25hp motor?

 

[Johny25]

I have no need to continue debating something I am correct about. I have first hand experience with this mod and have walked many others through it. What the OP chooses to do is his choice. . My boat isn't going to go any faster whether he does or not :lol:

 

[MDCrappie]

Johny25 » Sun Jan 26, 2014 11:40 am[/url]"]I have no need to continue debating something I am correct about. I have first hand experience with this mod and have walked many others through it. What the OP chooses to do is his choice. . My boat isn't going to go any faster whether he does or not :lol:

Gotcha - so YOU never have done this on a 1982 yourself....you've "walked others through it".....in your own words.......

Johny25 » Sat Jan 25, 2014 5:56 pm[/url]"]

Listen to those that have done it.....not those that talk about doing it.

I'm done here......................you can go ahead and get the last word in now......

 

[BloodStone]

UGH This is INSANE!! ](*,)
Sorry, this may rank as blasphemy here but, I'm going to iboats.com & ask over there!
In the words of the late, great Jimmy Hendrix; "There's just to much confusion, I can't get no relief."

 

[Lil' Blue Rude]

BloodStone I'd listen to Johny25 on this one. He's put a lot of time and research into his carb swap and documented it pretty thoroughly. I don't think it would be that big of a deal to swap them out. If it was me it wouldn't bother me in the least bit to swap the carbs out.

 

[Charger25]

opcorn: opcorn:

 

[Boat2fast]

I may be able to help here. My experience is mainly 1987 and up 521cc (20,25,28,30hp). The largest carbs were used, mostly, on the top hp models with electric start and remote control. Please note that the top horsepower models have a different block. These engines typically had a cylinder-block part number all their own. The difference is the ports. The ports in the high-hp blocks are large oval shaped ports versus the small round ports in the standard blocks. I only figured this out when I had two blocks, all apart, side by side. Only the 35hp blocks(up to 85) and the 30hp(86 and up) had the big ports. These are the engines that got the big throat carbs.

With this all in mind...any engine can benefit from a larger carb, somewhat, as long as the rest of the system is capable of handling the increased flow. What flows in, plus combustion gases, must flow out. The engines with the larger ports always had a higher RPM operating range. They all had the larger lower unit too....as well as the big carbs.

Starting with the first "28hp" model(1986), the factory used the biggest practical carburetor on a small port block...still with the small lower exhaust system. This is the carb that will work best hot-rodding a 25. Finding a parts motor is the easiest thing, they are everywhere. Sticking a 30-35hp carb on a small port block, with the smaller exhaust, is something I would never have even tried. The carb would likely ruin the responsiveness of the original engine. Endless time could be spent re-jetting and adjusting...blah-blah...all to frustration.

Remember the factory had unlimited time and resource to play with all sorts of these combinations. Following their lead is easy with factory parts books. These detail all the combinations of parts that worked best. The best ones they sold to us.

Final results, for me, stay with the 85 and up years. All the bugs worked out. Large gearcase equals best flow and much better prop selection. Going fast?... find a big port block. Then get out your big carburetor.

Word of caution. Small 12-14ft aluminum boats get real dangerous with the right combination of horsepower, mounting height, trim angle, and prop pitch. My best efforts to date have turned over 40 mph running 6000 rpm with 17p factory sst prop. Many years of seat-time with tiller engines and light boats has taught me fear. Picture a stone skipping across the water. My 2c worth.

 

[Johny25]

Notice these guys that race and have actually done this mod talking about the 35hp carb bolting directly on the early 80's models.....and also the pics that are posted. The top 2 motors are pre 85' 25hp engines with the smaller exhaust that flows out behind prop. I highly doubt they would invest the money into a racing gear case like that unless the mod works and works well.

https://www.boatracingfacts.com/forums/showthread.php?10871-omc-25hp

 

[Johny25]

And just for the record.....I have never advised anyone to do this mod to a pre 85' motor with the smaller gear case. Although many guys have went ahead and did it and apparently had no issues. OMC was the best outboard manufacturer back in these days and made some great stuff so I do not doubt that the smaller gear case can handle it.....i just don't put my name on it.

Here is the motor I did the mod to. And remember my 14' tin is decked out and very heavy, around 1200 lbs total weight in these videos. Going into a headwind and up current on a river mind you and I am still doing 28mph
https://www.youtube.com/watch?v=VMeGmnCff6I&index=2&list=FLguJ4E_MdXrMCCB2b8no36Q

 

[BloodStone]

Ok, I just called my local marine dealer & I found out the carb # on my 1982 25hp Evinrude E25CNE is #393017 &
the 1982 35 hp E35ECND is #393057. And the gentleman said, the carb kits for BOTH carbs are exactly the same. The only difference between the two is the 35 has a larger jet size. He said even the intake gaskets (throats) are the same (so is the housing size). In short, he said there should be no problems. And he said, the LU shouldn't be an issue either. At worst, I might have to change props to allow for RPM issues. He also said if I was going to use a 25hp carb off a long shaft 25hp Johnnyrude onto a short shaft 25hp Johnnyrude then I might have issues (probably with exhaust). I did hear from a guy at iboats who said that the internet is a "great source for a wealth of bad information." So I think I am leaning toward getting the 35hp carb..:-k

 

[Boat2fast]

OKay I understand where your parts guy is coming from. The kits are the same, and so are the mounting gaskets. I stock them all the time. But the jets are NOT the only difference. Look at the picture. Here is a 25hp carb(on the left) next to a 30hp carb (on the right). The 25, 28, 30, 40, 50, 60, 70 and 75s also use the same kits as long as the carbs are the same style. The carbs are different in their venturi diameters. Again more power requires more air(bigger carb). More air requires more fuel(bigger jet). I don't usually bother with the smaller exhaust, old style, lower units because the prop selection is limited. As soon as you get them running good, you can't find a prop big enough. They just over rev and bounce off the rev limiter. OMC never put the big port blocks and big carbs on the old style lower units. I follow their lead.

 

[Boat2fast]

I got caught once believing I could re-jet a 30hp Mercury to 40hp specs. Both engines had identical carbs according to the parts books. The only difference was the jet part number.
I bought the big jet and installed it in the original carb. The engine started and ran normally. I motored out of the mooring area and gave it the gas. As soon as the engine started drawing fuel through the main jet, the motor chugged and gagged from way-to-much fuel. I restored the old jet to its rightful position and the engine ran perfectly once again. Later I looked down the throat of a similar 40hp engine and, lookee there, a much bigger carb.
Here is some actual practical experience for you. You can learn a cheap lesson that cost me time and money.
Compare a 9.9 and a 15hp carb. You will see the same thing. Same with a 40 and a 50hp carb. All these carbs show every part number the same except the jet.
Please see attached two photos of OMC 40 and 50hp carbs. The bowls are missing from the 50hp units. The 40hp units are obviously smaller and flow much less air.
There are often other changes in the various parts of identical engines. One to be more powerful and one to be less. For instance the 1988 OMC 50hp cylinder head has a smaller combustion chamber than the 40hp head. This results in a higher compression ratio. This compliments the larger carbs and the engine makes more power. Sometimes the reed valves are the same but the fingers are allowed to open a little farther. Sometimes the exhaust tuner is larger or smaller(9.9-15hp 1980s). Sometimes the actual block is different with larger ports (later 40-50hp).

 

[BloodStone]

Boat2fast » Mon Jan 27, 2014 9:32 pm[/url]"]OKay I understand where your parts guy is coming from. The kits are the same, and so are the mounting gaskets. I stock them all the time. But the jets are NOT the only difference. Look at the picture. Here is a 25hp carb(on the left) next to a 30hp carb (on the right). The 25, 28, 30, 40, 50, 60, 70 and 75s also use the same kits as long as the carbs are the same style. The carbs are different in their venturi diameters. Again more power requires more air(bigger carb). More air requires more fuel(bigger jet). I don't usually bother with the smaller exhaust, old style, lower units because the prop selection is limited. As soon as you get them running good, you can't find a prop big enough. They just over rev and bounce off the rev limiter. OMC never put the big port blocks and big carbs on the old style lower units. I follow their lead.

Interesting. :-k
These 2 carbs ARE the same style (& same size housing too). But what if I do what Johny25 said & put a intake plate off a 1984 35hp Evinrude (providing it bolts up the same) onto my 25 along with the carb (thus accomodating the larger throat size)? Outside of maybe the prop, what other changes would I have to make if any, enlarge the exhaust tube/port...what?
And as you probably already know, both the 25hp & 35hp Evinrude carbs are no longer available or apparently being manufactured.
So you can maybe understand my desire to get this carb to work on my motor.

 

[BloodStone]

Boat2fast » Mon Jan 27, 2014 9:32 pm[/url]"]OKay I understand where your parts guy is coming from. The kits are the same, and so are the mounting gaskets. I stock them all the time. But the jets are NOT the only difference. Look at the picture. Here is a 25hp carb(on the left) next to a 30hp carb (on the right). The 25, 28, 30, 40, 50, 60, 70 and 75s also use the same kits as long as the carbs are the same style. The carbs are different in their venturi diameters. Again more power requires more air(bigger carb). More air requires more fuel(bigger jet). I don't usually bother with the smaller exhaust, old style, lower units because the prop selection is limited. As soon as you get them running good, you can't find a prop big enough. They just over rev and bounce off the rev limiter. OMC never put the big port blocks and big carbs on the old style lower units. I follow their lead.

Ok I hear what you're saying Boat2fast (& no I'm not questioning your mechanical mojo lol) but then on the other hand, I find stuff like the following..https://www.boats.net/parts/detail/brp/B-0386792.html And when I go on ebay I also find that besides the intake manifold, the Inner Exhaust Tube Housing between the 25 & 35 are apparently the same too, etc..Now how can the carb housing be the exact same size, the intake manifold the same & apparently the Inner Exhaust Tube Housing between the 25hp & the 35hp too? Seems like there isn't a whole helluva lot of difference between these 2 motors. So with that said, Do you have any links that show an exploded diagrams of these two OB motors (the 1982 25ECNE & the 1982 35ECND)? Maybe that'll help clear all this up for me. Also, IF I do get that carb plus change out the intake, you're telling me, it's a fool's errand & that it unquestionably will NOT work, correct?

 

[Boat2fast]

Okay, we're comparing the 1982 25hp and the 1982 35hp. What are the differences? Different part numbers mean different parts.

Block 25hp: #0390430, 35hp: #0391166

Head 25hp: #0327671, 35hp: #0327672

Carb 25hp: #0393017,0393020(15in or 20in), 35hp: #0393057 all models

We know the block is different.
We know the head is different.
We know that the lower unit is the 'new style'.
We know the carb is different.

Now we need to examine the parts themselves to determine what changes the factory engineered to make more power. I have not done this with the 1982 models.

On the later models the 30hp blocks have much bigger ports. 1982 is the same. The 2 block numbers supercede all the way up to 2005.

Different cylinder heads usually have different combustion chamber volume. This results in higher compression ratio. (I measured chamber volume in the 1988 40hp and 50hp heads. 34cc vs. 31cc)

Different carbs have different bore sizes. Small carbs allow less air flow. Bigger carbs allow more. Big carbs don't meter fuel as precisely at low speeds as small carbs do.

The RPM range is higher on the 35hp models to take advantage of the added flow capabilities. Example: 1983 25hp runs 4500-5500rpm, 1983 35hp runs 5200-5800rpm. Note the 35hp 'RPM range' is higher and narrower.

These differences combine so all the parts work in harmony together. A higher horsepower engine needs ALL it's parts to do their job to the same degree.

This is why putting a 35hp carb on a 25hp engine probably won't do what you are hoping for. It may actually ruin the low speed responsiveness that the 25 had before. All the rest of the '25hp' parts are all at their limits just as the big carb is ready to start working.

 

[Johny25]

Boat2fast » Today, 12:03[/url]"]Okay, we're comparing the 1982 25hp and the 1982 35hp. What are the differences? Different part numbers mean different parts.

Block 25hp: #0390430, 35hp: #0391166

Head 25hp: #0327671, 35hp: #0327672

Carb 25hp: #0393017,0393020(15in or 20in), 35hp: #0393057 all models

We know the block is different.
We know the head is different.
We know that the lower unit is the 'new style'.
We know the carb is different.

Now we need to examine the parts themselves to determine what changes the factory engineered to make more power. I have not done this with the 1982 models.

On the later models the 30hp blocks have much bigger ports. 1982 is the same. The 2 block numbers supercede all the way up to 2005.

Different cylinder heads usually have different combustion chamber volume. This results in higher compression ratio. (I measured chamber volume in the 1988 40hp and 50hp heads. 34cc vs. 31cc)

Different carbs have different bore sizes. Small carbs allow less air flow. Bigger carbs allow more. Big carbs don't meter fuel as precisely at low speeds as small carbs do.

The RPM range is higher on the 35hp models to take advantage of the added flow capabilities. Example: 1983 25hp runs 4500-5500rpm, 1983 35hp runs 5200-5800rpm. Note the 35hp 'RPM range' is higher and narrower.

These differences combine so all the parts work in harmony together. A higher horsepower engine needs ALL it's parts to do their job to the same degree.

This is why putting a 35hp carb on a 25hp engine probably won't do what you are hoping for. It may actually ruin the low speed responsiveness that the 25 had before. All the rest of the '25hp' parts are all at their limits just as the big carb is ready to start working.

Ok rather than debating this anymore I ask you to find 1 person who has ACTUALLY done this modification who has not seen good to great results. There are plenty of people who haven't done this modification that say it can't be done or shouldn't be done........yet there are plenty of people that have ACTUALLY done it and had good results including myself. Of all the people I have walked through this mod in the past I have not had one of them say it did not work. I am not telling the OP to do this mod as I have never told anyone to do it.....what I am saying is it can be done and has been done with success......end of story.

 

[MDCrappie]

Johny25 » Wed Jan 29, 2014 4:52 pm[/url]"]

Ok rather than debating this anymore

Well then STOP debating. I gave advise, you gave advise (then had to debate) and now someone else is giving advise (and you have to debate). Just because you keep saying the same thing over and over that doesn't make it right.

The OP has the info now, let HIM decide.

 

[Boat2fast]

Here's one that did work. 2003 25hp pull start, shortshaft. Put on a brand new 30 carb, Panther power trim, and a 15p Stainless prop. Boat did 40gps

While holding on, trimming, and steering, I had barely a second or so to look at the GPS. Here's a link:

https://www.dropshots.com/boat2fast#albums/Running Videos/2008-08-14/13:21:30

If asked for a guest password, use "twist'er"

The engine is now property of some thief.

 

[BloodStone]

Boat2fast » Wed Jan 29, 2014 6:32 pm[/url]"]Here's one that did work. 2003 25hp pull start, shortshaft. Put on a brand new 30 carb, Panther power trim, and a 15p Stainless prop. Boat did 40gps
While holding on, trimming, and steering, I had barely a second or so to look at the GPS. Here's a link:
https://www.dropshots.com/boat2fast#albums/Running Videos/2008-08-14/13:21:30
If asked for a guest password, use "1914"
The engine is now property of some thief.

Man, I am really sorry to hear that boat2fast. :-& Was it covered by your insurance?
Anyway, after a 1/2 phone call to a local marina, I've decided to get a carb kit & 2 new gaskets instead (1 of them being an intake). The man said that unless the carb body itself is damaged just rebuild it. He also said that he suspects an air leak (aka running lean) & thus the reason I'm having to choke it at wot. And finally he said, the gear-case is different between a 25hp & 35hp & it would almost be the equivalent of putting a Chevy 350 cubic inch engine in a car that originally only had a 305. In short, the tranny (I.e gearcase) may not hold up. So I'm going the route of rebuild. And just to cover my bases, I am also buying a new choke solenoid too. If that doesn't work, I'll sell the #@%&$ thing (after Hulking out-natch! :lol: ) & put on another Johnnyrude when it's financially feasible to do so. Which leads me to my final question, if the latter scenario proves out to be the case, do I need to necssarily find a non-tiller ONLY JohnnyRude (1985 on up) or can those be converted from tiller to controls without too much hassle?
Thanks for all your input guys much appreciated. :beer:
Edit: See this link for even MORE confusion & uncertainty. ](*,)
https://forums.iboats.com/johnson-evinrude-outboards/converting-20-hp-johnson-35-hp-274566.html

 

[SumDumGuy]

rebuild the carb and it should run fine (this will be considerably easier to do than the afore mentioned carb swapping debacle). :twisted:

Why worry about the solenoid at this point? You can apply and release power and watch it actuate.
At worst you can always disconnect the solenoid powered choke and use the manual. It's not like it's needed at WOT (at least not when the carb is functional :LOL2: ).