V4 Evinrudes

[Yalta]

Am I correct in thinking that the bore and stroke on a 1981 90Hp evinrude is the same as a 1984 140hp Evinrude?<br />They are both crossflow engines.<br /><br />I only ask as I wish to use parts from the 140Hp which needs a rebuild to give the 90Hp more power.<br /><br />If I can which parts are different?<br />Which exchanges would give me the most benefit if exchanged?<br />Thanks any help would be great.

 

[noelm]

Re: V4 Evinrudes

Don't really know about 81 models but later they were very different, the 90 and 115 were similar, and the 120 and 140 were similar but 90 and 140 not the same (at least after about 1986 that I know of)

 

[WillyBWright]

Re: V4 Evinrudes

If I'm not mistaken, the 90-115 V-4s are Crossflows and the 120-140s are Loopers. Same bore, different pistons and porting.

 

[noelm]

Re: V4 Evinrudes

once again not too sure but i think the 120-140 is a bigger capacity engine as in about 2 litre where as the the 90-115 is only about 1200CC (I think)

 

[Yalta]

Re: V4 Evinrudes

The specs sheet I have on the 90hp (E90MLCIM) says displacment of 1632cm3 the same as the same years 115hp and 140hp. Bore and stroke are listed as the same (88.90mm bore X 65.74mm stroke).<br />Unfortunately I only have the details for the 90hp not the 140hp.<br />I will post the serial number, as it is in storage in another town, but I will drive up there today and have a look.<br />thanks for the input.

 

[noelm]

Re: V4 Evinrudes

hhmmm did a bit of a look and it seems in the early days they did indeen make a 115 and 140 that were the same but in the later years like after 1985 or so they were different

 

[noelm]

Re: V4 Evinrudes

back to the first question that you want to rebuild a 90 with 140 parts, I think you would need to be a real expert to know what to use and what not to use to ensure proper rebuild, why not rebuild the 140 and be sure of what you get? because you could get into trouble with running lean or something like that if correct parts are not used.

 

[Yalta]

Re: V4 Evinrudes

it's not a rebuild on the 90hp.<br />It works well, I just thought if its bolt on power why not use it.<br /><br />I had been told that the exhaust plate and carbs were the only difference.<br /><br />I got the 140hp cheap and thought why not use it.<br />I really don't want to rebuild it.

 

[Dhadley]

Re: V4 Evinrudes

Its a direct bolt on between the 81 90 and the 84 140 crossflow. The difference is in the port timing and the exhaust. Depending on your set up you may be real disappointed after all that work. <br /><br />Are you sure the 90 set up is maxed out? Does your hull respond well to small increases in torque?

 

[Yalta]

Re: V4 Evinrudes

Not sure on response of the hull, I've only just purchased the boat, a 18' 9" YaltaCraft<br /><br />I have found it to be drastically underpowered with the 90hp on it.<br />I also work in the industry and have George from Yalta as a customer, he says I should at least have a 115hp on it.<br /><br />However in saying that I've also found that the WOT stop to be adjusted incorrectly, so that the carbs couldn't open fully.<br />This combined with the 14" x 17" alluminium prop,<br />WOT was only at 3800rpm.<br />I have changed the prop to a 13 3/8" x 17" S/S prop and adjusted the WOT stop to allow the roll pins on the carbs to touch the stops on the carbs.<br />What else can I do to ensure I'm getting the most out of the 90hp.

 

[Rudy Brown]

Re: V4 Evinrudes

Dhadley, What is "port timing"?

 

[Dhadley]

Re: V4 Evinrudes

Port timing is where the port is in relation to the piston travel and deck height. It also has to do with port opening area. IE -- the location of the port and the size of the port opening.<br /><br />Its a lot like the cam in your car. Intake port timing lets a given amount of the fuel / air mix in at a given time. The exhaust port lets a given amount out at a given time.

 

[Dhadley]

Re: V4 Evinrudes

You need to get the 90 to about 5800 with a given load. If, with your changes and a healthy 90, lets say you get 5000 with the 90. Just bolting on the 140 powerhead is not necessairly going to automatically get you to 5800.