1990 evinrude 120 4600rpm WOT enough?

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

I am more than happy to send you a 13 spline 13 x17 prop for your new LU u pay shipping or pick up.

That would be awesome. Right now I'm just waiting on a foot to come across craigslist.

 

[nymack66]

Re: 1990 evinrude 120 4600rpm WOT enough?

That would be awesome. Right now I'm just waiting on a foot to come across craigslist.

You need a 20' or 25" ? Let me know your price range and I will let you know I have a few locals I can check with...

 

[wilde1j]

Re: 1990 evinrude 120 4600rpm WOT enough?

You might try here:
http://www.sterndrive.cc/mm5/merchant.mvc?Screen=CTGY&Store_Code=SE&Category_Code=SE305

BRAND NEW for under $800 with a guarantee. That's close to what you'd pay for a CL used one!!!

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

It's a 20"

 

[nymack66]

Re: 1990 evinrude 120 4600rpm WOT enough?

You will need to confirmed if its a 20" with 13 splines ...
http://orlando.craigslist.org/boa/1909489119.html
http://orlando.craigslist.org/boa/1929221871.html

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

UPDATE

I've just purchased the V4 13 spline lower. As soon as I've got it on and have results I'll post them. I expect the shop the motor came from will do another straight swap on the props for me for a 13 spline.

Also I ran it with just me and the dog on it yesterday with perfect conditions, and going from the 19 down to the 17 pitch did up the RPMs to 4900 when it was fully trimmed out on flat water.

Hopefully there will be results to post sometime next week.

 

[ezeke]

Re: 1990 evinrude 120 4600rpm WOT enough?

xxxxxxxxxx

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

mulligan..

Let's just call it 'significantly not as described' and 'not the item pictured'

So as soon as I finish this return business, I'll try again.

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

]

Update-

I did finally find myself another lower unit, and the WOT throttle hit 5500+ no problems even running the 15x17 prop the shop gave me back then. I actually went with another 15 spline but it's the correct large gearcase for 140 this time around. Also reset the linkages and swapped the powerpack in the meantime and that upped the RPMs a bit before the changeover and helped the idle a lot. The whole electrical system was a mess but long story short it's all cleaned up now.

I'll be going back to a higher pitch asap because on this gigantic low pitch prop it went that high with 3 passengers in horrible chop and zero trim. I wasn't even able to just let it sit WOT for long enough to level off and find out the max because of the chop and how fast it was already going. MY GOD this thing gets up and goes now! It had a lot of *** to it before but now it has gone from feeling like a fast car with massive turbo lag to touching the throttle and being shot out of a cannon.

It also trolls against the heaviest currents in dead idle without dying now!

Thanks everyone for the advice esp nymack66

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

I want to get off of the 15" 17p prop now but don't seem to have a lot of options to fit the 15 spline gearcase.

Is this just a matter of the hub? Can I buy the size and pitch I want and then just swap in a 15 spline hub?

 

[nymack66]

Re: 1990 evinrude 120 4600rpm WOT enough?

I have a 14 x19 stainless 15 spline if you are interested let me know ...

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

I have a 14 x19 stainless 15 spline if you are interested let me know ...

I may just take you up on this. I guess it's the powerband having been drastically moved around, but it porpoised hard with this gearcase and no fins. I didn't notice the first few times out because there was a good bit of chop that week. With the fins put back on it's much better but by no means set up right.

So I went to a prop shop a few weeks ago and the guy said I had two obvious problems-

1, that the motor is mounted too low. My cavitation plate is level with the very bottom of the keel, but look at this picture. It actually rides at that level where the tansom dips back in toward the keel when it's on plane. That's about where it floats, too. I inspected it at cruise speed and it is a bit below the water level and looks like it's really forcing water where it doesn't want to be. It can go up about 3-4" before it gets above there. He tells me this is the main cause of the porpoising. Makes sense.



2, the wrong prop. He loaned me a 14.25x21. With 5 people + the german shepherd it didn't like it. 4100 RPM @ 33mph and 7-10 seconds struggling to get on plane. Just me and 1 passenger and it planed much faster but just 4800rpm, although 43mph. I thanked him and gave it back.

Here's the current situation: me + 1 or 2 people and the 15x17 there is no wait time to plane- you hit the throttle and it just lifts vertically out of the water, no appreciable bow rise to speak of. ~5700rpm at 42mph is the max I've hit. It HATES trim unless the water is flat and it's at WOT. Even then I can barely trim it out at all. It loves dead bottom zero trim at 3800rpm 27mph, and has a gentle but always present bobbing. Not enough to complain about porpoising.

I haven't gotten around to remounting it. Every weekend has been some holiday that requires a boat, out of town guests so I need the boat, etc. Things that just make you think "hmmm it works right now. don't. touch. anything." That and a bit of laziness. Well this weekend there's nothing going on and it's going to rain so by god it's getting remounted.

As for the new mounting, what's a good sealer? I'm assuming no adhesive sealer for this? The two appropriate seeming ones I have on hand are West's polyether caulk and 3m silicone.

 

[metriccrescentwrench]

Re: 1990 evinrude 120 4600rpm WOT enough?

The proper sealer for sealing engine mounting bolts would be 3M 5200. You DON'T want to use inferior products and let water penetrate the wood in your transom.

5700 rpms at WOT sounds pretty good.

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

The proper sealer for sealing engine mounting bolts would be 3M 5200. You DON'T want to use inferior products and let water penetrate the wood in your transom.

5700 rpms at WOT sounds pretty good.

Is it going to be a pain in the *** next time I go to remove the bolts with that 5200? The adhesive part is my concern.. But that's way off in the future

The 5700 rpm part is great but as I understand it it's going to take a lot of load off of the drivetrain when I move the motor up because it will be pushing the boat from a softer angle which it seems ought to raise the max RPMs?


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[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

Finally moved it last night. It was at the deepest setting out of the 4. I moved it up 2 holes so there's one left. In hindsight I wish I'd just moved it all the way up. Will post results once it's cured and I get it in the water.

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

Videos of where the cavitation plate was running at about 3200rpm:

It ran pretty well but I am not sure whether it's in the right place yet. It seemed like the porpoising is fixed but I won't know for sure until I can run it in really flat water and see how it does. Sometimes the waves can keep it banging around enough to hide that. Trimming it didn't do much good but I wasn't running much WOT due to conditions. I can say though that trimming it didn't cause terrible porpoising the way it used to when I even looked at the trim switch..

Planed at much lower speeds. I was able to hold a comfortable plane at 16mph without getting easily knocked off by waves.

It ran a lot smoother through the waves and held the bow down into the chop a lot more effectively than it did before. It used to beat me up going at high speeds into moderate chop but it held the bow right into it all day.

There wasn't much flat water to test the max RPMs but at one point it did hit somewhere around 5900 against a heavy wind and in chop so some progress there. I'll have to wait and see what it wants to do in some glassy water.

When I swapped from the V6 gearcase to the V4 it lost the 3000rpm 22-24 mph cruise and would sometimes fall off plane or lose rpms at less then 3400 and began to love 3700 or so. Now with it mounted higher it comfortably cruised right around 3000 at 24-25mph all day. That was awesome for fuel efficiency. I have two 12 gallon tanks, and one was dead empty and I put 9 gallons in it. The round trip was about 24 miles with about 45 minutes at a fast F idle, and it started sputtering about a half mile from the dock. Not bad for the big V4!

So there were definite performance gains from moving it up. Can someone give me an opinion on how the cavitation plate's positioning looks in those videos?

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

I personally lobby for photos a million times over. Very few will post...They are priceless..
Your gear case is V6 and needs to be swapped out.
Your carbs clearly shows 140 hp not 120 if it was a 120hp you will not even see close to 4k rpm !
Post the numbers on the jets exactly how they are installed currently, I wanted to make sure you are jetted correctly.

Ha it's a Johnson J140TLES! I called BRP. I never called before because my neighbor at the time (yacht mechanic, and not one of the ones I demonize all over these posts, he was generally quite helpful) told me the numbers on my specific welch plug were garbage, likely a replacement part of some kind, and of no use. He'd never steered me wrong so I took him at his word. I swear I must have called this motor 5 different things on these boards but finally it's settled.

+1 on the 3 screw butterfly 140.

BTW nymack I'm still interested in the prop business but currently have another project going on with my heads and thermostats in another thread.

 

[wilde1j]

Re: 1990 evinrude 120 4600rpm WOT enough?

You need to check for motor depth at or close to WOT. 3200 RPM doesn't tell a thing, other than the AV plate's buried. The AV plate should be DRY on top when right. BTW, I thgink 3M makes a 5200 debonder, if you need to move the motor any more.

BTW, the HD gear case is the correct one for an '85 120/140 and as Boobie pointed out didn't have thre same gear ratio as the V6's. I owned an '85 140 for over 20 years ... great motor.

 

[archcycle]

Re: 1990 evinrude 120 4600rpm WOT enough?

I did check it at WOT and it looked right about the same so I just shot the video at cruise because it seemed safer leaning out over the transom holding my 6th iPhone

Perhaps I need to try it again without the fins and see what I get. I did notice that it was easier to make it ventilate a little bit going over large chop so I'm hesitant to move it higher. It's got one higher setting left. As you can see it certainly wasn't dry. It also threw up a lot more water than it used to around the plate. It used to be a little submerged but was very calm right around it. Maybe that does mean I have to just raise it again cause it's almost there.

And yeah great motor. Now that most of the issues are worked out it seems just bulletproof and I don't even mind putting more money into it. Pretty reliable for '90

 

[cdn-pk]

Re: 1990 evinrude 120 4600rpm WOT enough?

just out of curiosity how did you raise it? Shop Crane? Jack?