Evinrude 140 parts on a 90

[Yalta]

I have a evinrude 90 (1981) on my 18'9" fibreglass half Cabin.<br />I also have a 140 (1984) that I bought for parts.<br />Can I put the Exhaust Bubble and carbs from the 140 on the 90 to get more power?<br />If so what sort of life should I expect from the engine?<br />Am I correct in thinking that the difference between a 115 and 90 is the carbs and exhaust bubble?<br />Then with larger intakes on a 115 becomes a 140? (same carbs and bubble)<br />The 90 is sound but slightly underpower for the boat..<br />Thanks

 

[Dhadley]

Re: Evinrude 140 parts on a 90

The parts will fit, no problem. What youll end up with is a 90 that burns more fuel and probably wont be any faster on top end. The holeshot may suffer also. <br /><br />With those parts your 90 can be converted into a 140 (or 110, 112, 115 -- whatever you chose to call it) but youll have to pull the motor apart and change the port timing to the 140 specs. No big deal once you have the motor apart. But I'd bet you'd be disappointed with the results vs the $$ spent.<br /><br />I'd also bet you can gain as much or more by dialing in what you have now. If your currect set up is off now, simply throwing more gas at it wont help. <br /><br />Tell us more about your current set up -- top accurate speed, top rpms with average load, what prop etc.

 

[Yalta]

Re: Evinrude 140 parts on a 90

Currently WOT RPM 4800 with a 13 3/8" X 17" S/S prop, max speed of 63 kph. <br />I'm thinking of changing the prop to a 13 3/8" X 15", to see if I can get a little more RPM out of it. I've only owned the boat for 3 months and have a few things I'd like to change.<br /><br />After talking to the Bloke who made my boat he said it is best served by a 115, and slightly underpowered with the 90.<br /><br />What would be the best way to maximise what I have now?

 

[MGuckin]

Re: Evinrude 140 parts on a 90

Do you have a picture of the motor and how it is mounted? Where is the plate in relationship to the bottom of the hull? RPM @ WOT is way to low.

 

[Yalta]

Re: Evinrude 140 parts on a 90

I'll take one in the morning and post it tomorrow night after the footy.<br /><br />I was only getting 3800 with a 14" X 17" aluminium prop that was on it when I bought it.<br />I changed the prop and had a look at the linkage settings and got another 1000rpm out of it.

 

[Dhadley]

Re: Evinrude 140 parts on a 90

Truthfully, I doubt youd see any difference from a properly set up 90 crossflow to a 115 crossflow. Now going from a 90 crossflow to a 115 looper youd see a lot of improvement.<br /><br />Lets look at the tach first to make sure we're OK there. I suspect we are. It should be on position 6 but lets check.<br /><br />At 4800 were looking for 1000 rpm so its going to be more involved than a simple prop change. I think Mike is correct about the height (X dimension) being too low.

 

[Yalta]

Re: Evinrude 140 parts on a 90

I've checked on 2 different Tach's as the one fitted to the boat doesn't have a dip switch to change settings.<br />I did check on a omc one set on 6.<br />And it read the same as the one fitted.<br />I do notice if I trim up I certainly do get a little extra legs from it.

 

[Dhadley]

Re: Evinrude 140 parts on a 90

I figured the tach was OK but it never hurts to check. And yes, trim is vital to getting the proper rpms. As you trim up you reduce the wetted surface of the hull which reduces drag. That will result in more rpms. Now, is 4800 when its trimmed up?

 

[Yalta]

Re: Evinrude 140 parts on a 90

Yes 4800 is when I trim up. But there is only maybe 200 rpm in it.<br /><br />Not really a lot.

 

[Dhadley]

Re: Evinrude 140 parts on a 90

Can you use all the trim range without venting the prop?

 

[Yalta]

Re: Evinrude 140 parts on a 90

not sure I'll drop her in the water and see.<br />I have the biggest game of footy for the year tonight so I'll see if I can get her in before hand. If not it'll have to be Friday morning.<br />But I'll post the result.<br />thanks for the help so far..

 

[Dhadley]

Re: Evinrude 140 parts on a 90

Cool...keep us posted.

 

[Yalta]

Re: Evinrude 140 parts on a 90

I haven't had a chance to do the photo's.<br />But having a look when I finished work.<br />The hull of the boat has a flat centre about 6" across and my Hydrofoil is near perfectly inline with the bottom of my hull.<br /><br />Using a straight edge along the bottom of the hull, my prop has about 1/2" clearance below the hull.<br /><br />There is only about 3" of my gearbox is above the bottom of the hull.<br /><br />Not sure if this helps, but it may give you an idea.

 

[Yalta]

Re: Evinrude 140 parts on a 90

Hope this helps<br /><br />The engine is trimmed level<br /><br /><br />

 

[Dhadley]

Re: Evinrude 140 parts on a 90

It could be higher especially if youre going to use the fin.

 

[Yalta]

Re: Evinrude 140 parts on a 90

Thanks I'll move her up a hole and see how she goes.

 

[Yalta]

Re: Evinrude 140 parts on a 90

Could I use the buble off the 140 to get better exhaust flow?<br /><br />And what about the carbs.<br /><br />It's not gonna cost a lot.<br />So if I get any benifit I'll do it.<br /><br />Thanks

 

[Dhadley]

Re: Evinrude 140 parts on a 90

At 4800 the exhaust wont help. What you have now will flow more than 4800. Bigger carbs will hurt the holeshot. You still will have the 90 (small) ports and port timing.<br /><br />You need to optimize what you have now.<br /><br />Are you sure the 90 is running correctly? Is it indeed running on all 4 at wot?

 

[Yalta]

Re: Evinrude 140 parts on a 90

Yes, I've checked and found it to be running on all 4 at WOT. I'm sure of this as I did a coil on return from one of my trips, and had to limp back in on reduced power.<br /><br />I did notice that the butterfly in both carbs weren't opening fully at WOT.<br />(roll pin wasn't making the stop)<br />So after some adjustment it now does.<br /><br />I've lifted the engine one hole and will get it on the water tomorrow to see if its made a difference.

 

[Yalta]

Re: Evinrude 140 parts on a 90

Sorry it has taken so long to let you know about the outcome of the engine lift, I've been away for work.<br /><br />Anyway it seems to of made little difference, maybe 100-200 rpm and the boat seems a little light on the steering.<br /><br />I'm going to drop it back down a hole when I have a chance.<br />So I guess I'm now still searing for a solution.