1980 35hp Evinrude Motor Mods?

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mjw210

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Mankato, MN
I'm doing a complete rebuild of this motor. E35ELCSM
I'm getting it bored and oversized pistons. I've already sanded down the cast lines on the intake manifold and the intake side of the crankcase. I have a 16' Lund deep V-hull from the 80's. Refinished everything and converted to remote steering.
Is there anything else I can do to crank out a little more hp without making it unreliable.

Thanks,
Mike
 
A set of boyesen reeds may help with throttle response. Shaving the head will give you better compression. Putting a thinner head gasket on will also increase compression. I have also read in the past that people have re-worked the head, cleaning it up and porting it out due to the rather crude design of older 31.8 cube block and head.

There is a racing forum that I used to read a lot of good info on for tweaking the 31.8 ci OMC block but I cannot remember what it was #-o I will find it in my computer later today and post the link to it.
 
Any idea how much material can be removed? I could easily fly cut some material off the head. I have access to a machine shop I just wasn't comfortable doing the cylinder boring. Might look into the reeds if they still make parts for this old motor...
 
https://s1261.photobucket.com/albums/ii585/mjw210/

Pics of my rebuild progress and some of my old boat. :D
 
Wow great slide show and awesome project! First time I have seen someone post pics of inside the crank case, those pics are going to be handy to others also. Love the Lund too, my favorite tin :mrgreen: .

So were the cylinder walls scored? I see your compression was really low to start. What is your goals with this project, I mean are you looking to hit 35-40mph? A larger motor may be an easier option if you are looking for lots of speed.

I can't remember off hand how much to shave off the head. This 31.8ci block is raced in the 25hp class by a lot of people. Being that the 25 and 35hp have the same block. Your motor in 1980 was only putting out about 30hp due to it being rated at the flywheel though.

How much have you researched on this OMC block you got? The parts are very easy to find so you will never have an issue getting any part you need. I will give you plenty of dealers to order from if you want. I have a million questions to ask and more info to give but I have to get my kids fed.
 
Thanks for the compliments! I was only able to hit like 21 mph before but, I think the motor was on its way out at that point. I really don't know what to expect for performance out of this motor. I do have access to mills at work so I could flycut a few thousandths off the cylinder head. I cleaned up all of the motor pieces (other than the block) and sanded all the gasket surfaces flat. There isn't a lot of material that could be shaved off of on the cylinder head. I'm not sure how close the pistons will come to that area so, I might just leave that alone. I went to college for auto service and ended up being a maintenance mechanic. I pretty much taught myself how to use the mills and lathe at work. I'm not allowed to play around with the CNC machines though... I put a carb kit in tonight and preped all that stuff for reassembly.

For polishing the cylinder head and intake manifold should I just use like fine scotch brite pad? I already sanded all the cast lines down. Just not sure how much of a polish I should do on it...

Also, while I have it apart if there's any pictures you'd like me to take I'd be happy to take more for any how to's or just to have as a reference. Those were all with my cell phone so, for better definition I could use my Canon Rebel. And yes the top cylinder was scored but, I'm having both bored out. Going with the Wiseco oversized piston kits. I'm going to call the shop tomorrow and find out some more details of piston size and when it will be done. I didn't expect to be ready for reassembly this fast. I'm going to paint it the original paint colors (thanks to a retired co-worker of mine who was a boat mechanic up until 1980) He has tons of outboards at his place! Never knew there was a 1/2hp motor before until I visited him the other day for advice. And everything is restored already. Just amazing to see all of that history. He convinced me that going with the factory colors would help the resale value if I ever sold it. I was going to paint it go with my boat...

On a side note I do have a SS prop already. I forgot what pitch it was but, I will look at it tomorrow and let you know. I think I got a more of a midrange one.

I would be interested in hearing any advice or where to get parts and etc... I would like to get as much performance as I can but, keep it reliable. Should I throw a K&N filter on it? :lol: I pretty much have to work on this at night since I watch my boys while my wifes at work during the day. Gotta love the opposite shifts.... :( Only benefit of it is not paying day care. (almost 3 year old and an almost 2 year old) Definately fun though. Can't wait until I can take them on hunting trips and other fun stuff with me.

-Mike
 
How ironic..... I have 2 boys, ages 6 and 3 but soon to be 7 and 4, and my wife works a second shift as a nurse so I always have my boys in the evenings and have to either wait until the wife gets home late at night or I have to wait for weekends to do more complicated things. This year I have finally been able to do more being that the youngest is almost 4. I don't believe in daycare...... not even if it means I get to play with boats, motors and fish more. And that is saying something from me :lol:

As for the cylinder head...... There is not much that you can shave and I have read articles where the pistons end up smacking into the head so you may just want to leave that scenario alone. Especially if you are looking to have a reliable motor.

For the intake manifold..... you can port the intake a little by putting the gasket on it to see if there is any that can be removed allowing better air flow. I wouldn't polish the inside any better than say 150 or 120 grit sand paper, you want some turbulence to allow the fuel to break up or atomize when going through.

As for polishing the head.... I wouldn't mess with the intake part of the head because of the possibility of causing poor fuel atomization, but if you can get in there to polish the exhaust ports then I would do that.

I have always wanted to make a custom tuned exhaust for my 88' 30hp johnson. I did a modification to my 9.9 a few years ago which included putting the 15hp tuned exhaust on it. Then when I removed my 30hp powerhead I noticed it had a very similar square exhaust as my 9.9 had, which made me wonder how much I would gain if I had the equipment to make a round style tuned exhaust for my 30? Reportedly it added 1.5hp to the 9.9 mod I did.

Now there is also the ability to change the size of the jets in your carburetor, but this can be a tricky thing to get correct. And I haven't yet figured out where to get just the jets from. But this requires a lot of putting them in, testing and pulling them out until you get the desired performance. I have thought about actually putting a totally different and larger carburetor on my motor to see if I could get a few more HP but......... I run out of time and money to do these ideas usually lol. And the wife only has so much patience for my motor mayhem.

You can never take to many pictures, for your own reference and possibly others in the future. I have hundreds on my computer and try to remember to snap pics when I am tinkering on my motor so as to be able to explain to others better when I can.

21 mph most surely had something to do with low compression. You should be able to easily hit 25mph and possibly 30. And as for the prop, when you get your motor up and running and you get a tach on the motor we can get you dialed in on the best prop that will give you top performance. I am running a 14 pitch SS on mine and I get 28 to 31mph depending on how much weight I have in my 14' boat.

Ok well I rambled on enough for now...... sorry for the long message :oops:
 
I looked at that boyesen reed site and I wasn't 100% sure I put in the correct engine info. Because thephotos of the reeds didn't look similar to what I have. Would my motor be a type "except A"? The machine shop hasn't done anything yet! I was like wtf I'm ready for reassembly.

Here's the link to the reeds that I think are the right ones. https://boyesen.com/power-reeds-196.html

I added new pictures of my port matched intake to the carb gasket. Tapered the edge and smoothed everything out with a red scotch brite pad.

https://i1261.photobucket.com/albums/ii585/mjw210/D9E7B0D6-orig.jpg
https://i1261.photobucket.com/albums/ii585/mjw210/87404F4D-orig.jpg
https://i1261.photobucket.com/albums/ii585/mjw210/2C0A64F3-orig.jpg
 
Got any specs on an exhaust setup? I can aluminum weld and can make a flange easy enough on a mill.

Yeah I love spending time with my kids too. I'm going to be sad when they're both in school and I'm going to hardly see them... It's funny because I ramble on too.

Going to pick up another project this Saturday for free! Craftsman rider/bagger that just needs a hub on the mower deck replaced. It's probably 5 years old or less. Guess when you own a trucking company you don't fix things... Oh well I will gladly fix it and use it or sell it. My yard in town isn't that big but, what the heck... if you have it you might as well use it.

Have you guys installed those reed plates? I almost want to try the motor without any mods that I didn't do just to see how much power it has... I don't have a tachometer but, wouldn't mind installing one since I guess I'll be waiting on the machine shop for probably another week... I'm also waiting on my omc service manual as well... any idea what wires I would need to tap into for hooking up a tach?
 
I think they just have the wrong picture up on there website..... here is an ebay link with the same model number 128 reeds that you need in the flower style 8 pedal. Those ones on Boyesen website look like my 15hp johny finger pedals. I have not installed these reeds before so I cannot guarantee they will do a lot. Although I do know most all the racing guys run them to help holeshot because they open easier and faster. Also if they ever bust off and fly into your crank case they will not damage your engine like metal reeds will. I plan on putting some in this winter when I swap my powerhead with my other 30hp block that has much better compression. You may just want to run it fairly stock like you said to see if adding mods like this actually help. It is hard to find people willing to post actual gains before and after.
https://www.ebay.com/itm/JOHNSON-BOYESEN-REED-VALVES-B128-18-35-HP-OUTBOARD-/400148637577?pt=Boat_Parts_Accessories_Gear&hash=item5d2ab7a789&vxp=mtr

Nice work on that intake =D> Do you have the part number on that intake? It almost looks like the smaller intakes that was put on the post 1985 25hp and the 35hp up to 1983. In 1984 they started putting a larger volume intake manifold on the 35's and then the 30hp in 85 got it also, allowing more air flow. The 35 became the 30hp in 85 due to prop rated HP instead of flywheel. I had a really good post on this mod with pictures but cannot find it right now #-o. But here is a few pictures of the two side by side and the differences.

The larger post 83' 0396790 in front and the smaller pre 84' 0396788 in the back
DSCN6369.JPG

Here is the 0396788 (small intake) measuring 5 and 1/16" across and also has a shallower bowl and thicker area between the 2" and 3" mark on the tape as you can see
DSCN6371.JPG

And the larger volume 0396790 intake with a measurement of approx 5 and 5/16" across with a deeper bowl and narrower neck between the 2" and 3" mark on the tape.
DSCN6370.JPG

If it is 0396788 it is the smaller intake that was used until 1983 on the 35's and in 1984 the larger intake was introduced and those part numbers are 0391054 or 0395626 and superceeded/replaced by 0396790 and that is the one you want. You could reem out yours if you want but it would be much easier to buy one of the others. A lot of work to get it correct without going through the intake wall on accident. I put the pics side by side and I am sure you have the 0396788 intake. The bigger one is a must if you are looking to gain HP and performance. Much better air flow and will bolt right on with no problems.

I hope all this made sense.....it is late and I am tired :lol:
 
Oh now I remember why I advised people to buy one instead of reaming or porting there old one. I didn't take a pic of this when I had them off together but the larger intake is taller......meaning if you lay them both down flat with the carb hole facing up, side by side the 0396790 is fuzz more than an 1/8" taller (if memory serves me on the measurement lol) than the 0396788. So there is no way to ever ream the smaller one to match the air flow of the larger intake. It is just not possible with the smaller casting of the 0396788 mold.
 
Ok I couldn't sleep because I forgot to talk about the exhaust tube :lol:. This is all theory now so bare with me. The exhaust tube/horn you and I have is the square style. All the 20/25/30/35's came with this style. Now I know that the 9.9 johnsons (almost all of them) came with the same style square exhaust (see pic). The 15's that had the same block as the 9.9's had different exhaust tubes (and carb), also known as a tuned exhaust that added another 1.5hp. And I believe (in theory) that if you made a similar tuned exhaust to fit on the 20/25/30/35's it should achieve the same principle.

Here is a pic of the 9.9 square style similar to ours next to the tuned 15hp round style.
Exhaust_tubes1.JPG

This is just another one of my theories that may be way more work than it is worth. But it was just another thing I have thought about over the past year that could increase HP by allowing better exhaust flow and not sacrificing engine longevity. When I get me an aluminum welder some day I may make one to test my theory. I mean someone has to try these crazy ideas I come up with late at night right :lol:
 
Thanks for the link for the reed valves. I guess I will start looking for another intake housing. :lol: :D
 
Funny. That makes 3 of us that have wives working opposite shifts. We did it when our kids were smaller too.

Great thread. Keep it coming.
 
You can get it new online from several places like these. Boats.net is usually the cheapest parts supplier but may take a few more days to get to you if your on the west coast. And it is $27 cheaper through boats.net matter of fact.
https://www.boats.net/parts/search/BRP/JOHNSON/1986/J30TECDM/INTAKE%20MANIFOLD/parts.html
https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1986&hp=30&model=E30TELCDM&manufacturer=Evinrude&section=Intake+Manifold

I bought mine off of ebay for $40 I believe. You just have to be sure it is the correct one that your purchasing. I just did a quick look and there isn't any on ebay at the moment even though there are 2 on there that claim to be what you would want. If the part number is not one of the three I gave you then do not buy it no matter what the seller advertises. Lots of misrepresented parts on ebay unfortunately.

Hey Jasper :D How is the prop situation coming?
 
I have a question for you guys. The motor is the long shaft one. Would it make a big difference converting it to a short shaft? I do have a riser to raise it up since my boat was probably made for a short shaft. I think I'll just have to watch ebay for the intake manifold you suggested. Just can't justify $120 for an 1/8" difference. Maybe when I find a cheap one I'll change that and the reeds.
 
You may get less flex with a short shaft but it will cost you a few bucks to get the short exhaust housing and drive shaft. Probably a couple hundred bucks. That drive shaft runs $100 easily usually.

Money keeps me from going to crazy also. Well that and the wife :lol: I have to pick and choose my mods since I don't have an unlimited budget or otherwise I would have gotten a $1000 racing gearcase by now. A 1.50:1 gearcase would make a huge difference in top speed! My children's needs come first though, then the motor and boat, then the wife :mrgreen:
 
Hey guys just was wondering about this reverse lock lever I ran across. Will this fit the E35ELCSM motor I have?
https://www.ebay.com/itm/Johnson-Evinrude-OMC-outboard-10-15-25-35-hp-Link-Reverse-Lock-Lever-322949-Oem-/250408308140?pt=Boat_Parts_Accessories_Gear&hash=item3a4d7f8dac&vxp=mtr

I almost forgot that the motor flips up while in reverse. It doesn't have a tilt pin just a threaded rod with nuts on each end. I've tried to find the right pin or whatever is suppose to be there but, with no success.

I've only had this motor for a few years and only used it a handfull of times. I used to have a 25hp evinrude tiller that had a pin that kept the motor in place.
 
I guess there's more than one part I would need to fix the problem. Not sure why any of the previous owners would have removed it...

https://shop2.evinrude.com/Index.aspx?s1=1l7gfd4m0um0em6sc12s84q2f3&catalog_id=0&siteid=1
 

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