1985 Evinrude 60hp Flywheel

I have a 1985 60Hp Evinrude and am planning on doing some modifications over the winter to get me to my desired speed. I've read some articles on here recently about sending the flywheel off and having milled to gain a little bit of speed. I'm new to the word of outboard modification so I don't fully understand everything yet. I was wondering, is it a good choice to get it milled, or am I just asking for trouble in the future with reliability? If it is a good option, are there any specifications that I should stay inside to make sure it will work properly? Dimensions or weight reductions? Any comments or replies appreciated.

Thanks, Cal

If your engine is a 3 cylinder, a factory 1972 or 1973 ( one of the two ) 65 HP flywheel is supposed to be a a lighter weight option. 3 cyl. only. Easily recognized by it's short ring gear teeth. I picked one up for a 56 ci short shaft project awhile back. If you're running a two cylinder.......never mind. When referencing your motor, 2 or 3 cylinder, along with displacement might get you more accurate info. Between the years of 85 and 86 you could have a 2 cyl, a 3 cyl, 45 ci,( 2 cyl.) 49 ci, (3 cyl.)or a 56 ci. (3 cyl.)All labeled as 60 HP. Hope this is of some help!

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Originally Posted by Callum5009

I have a 1985 60Hp Evinrude and am planning on doing some modifications over the winter to get me to my desired speed. I've read some articles on here recently about sending the flywheel off and having milled to gain a little bit of speed. I'm new to the word of outboard modification so I don't fully understand everything yet. I was wondering, is it a good choice to get it milled, or am I just asking for trouble in the future with reliability? If it is a good option, are there any specifications that I should stay inside to make sure it will work properly? Dimensions or weight reductions? Any comments or replies appreciated.

Thanks, Cal

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Cal

you won’t see any top end difference, only benefit of a light flywheel is on the top bearing and even then you won’t be turning the rpm to warrant it.

what boat is it going on ?

What other modifications ions are you planning ?

It will be going on my Glen-L Tuffy. I can currently get 37mph with my 1981 Johnson 50hp with low compression (120 and 80) and a mangled aluminum prop so its not like I'm going to be getting 70mph with this motor or anything. I had planned on upgrading the carbs, getting velocity stacks, cutting an air tunnel in the bonnet, and doing some other small mods to it but all of those modifications were shut down by people on here that said it wouldn't gain me any top end speed. All other modifications that people have recommended have been way too advanced for me and have required taking apart the powerhead. I'm 16 and relatively new to this so I don't want to ruin my motor by making one stupid mistake. If you have any ideas or recommendations I would love to hear though!

If it's really 120 and 80 you're likely going to be taking the powerhead apart sooner than later.
Maybe this one still has compression but bad ign, lower, etc?
https://www.kijiji.ca/v-powerboat-mo...ationFlag=true

Those numbers were from the 50hp that is on the boat right now, not the 60hp that I'm planning on working on this winter. The 60hp is at 150 and 152psi.

Ahh
The other thread has good suggestions

you can cut the cylinder head some to bump compression or just run it the way it is. If you are looking for more top end you should build a little jackplate for it so you can raise the motor and gain some rpm. They will spin up with the stock porting if you raise them up.

We race the two cylinder on our critchfield, stock porting and compression limited to 160 for the class, great little motors that like to spin up

Your race, what are the chamfer rules with porting? Seen to recall an allowance someone mentioned during a conversation a while back?

I'd find a 78 -84 Chrysler 85 triple or Force till early 90s. Side bullet water pickups, 225lbs 20"W/O PT

Another is the 65hp twin from 78 on, smaller powerflow lu side bullet pickups, 49.9ci 3.375x2.8, twin carbs, good and light 185lbs , trick porting from the factory and responds will to 170psi. They changed the rating in the couple years forward but the lu is the ID. Hard motor to find but sometimes you find a cherry.

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Originally Posted by FMP

Your race, what are the chamfer rules with porting? Seen to recall an allowance someone mentioned during a conversation a while back?

I'd find a 78 -84 Chrysler 85 triple or Force till early 90s. Side bullet water pickups, 225lbs 20"W/O PT

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sst45 specs for porting, compression limited to 160lbs for our class, a good spec sst45 can be 170-180 with a decked block and cut to spec head.

Is it happy on pump with 170-180?

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Originally Posted by FMP

Is it happy on pump with 170-180?

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yup

the omc 60hp twin is one of the most popular motors in the world, dead easy to work on and dead easy to find parts. dont bother trying to make it even more powerful as from the motor you are using now the power of a decent 60hp is going to be a huge jump.. you will be surprised just how a good a strong twin omc is... your 50 with bad compression is about half the power of the good 60.. I wouldn't change the reeds or anything. cutting the flywheel will get you killed, leave that alone.. it also will not give you any more speed like said above... a nice prop once you know how it performs....