Topic: 1965 Evinrude Lightwin – Speed Question – Page 2

This topic has 32 replies, 14 voices, and was last updated 9 years, 5 months ago by fleetwin.

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June 16, 2015 at 1:18 am #18174
corythecowboy
Participant
quote Steve A W:

Cory
Screw the "T" handle clockwise, that will screw the valve closed.
And remember, The only dumb question is the unasked question!

Steve A W

Sorry, my computer misquoted on me. I meant to say how can I be sure it’s running on both cylinders?

Thanks,

Cory
June 16, 2015 at 1:56 am #18176
phil-b
Participant
See if it runs the same with one spark plug wire disconnected from the plug, and shorted to the head?
Shorting the spark plug wire to "ground" prevents arcing thru the coil casing to the magneto plate.
June 16, 2015 at 2:29 am #18178
westwind
Participant
Canada Member
3 HP isn’t going to plane a small boat with any sort of normal weight in it. That means you have a short displacement hull which is going to be slow. Calculation is about 8.6km/hr or a little over 5 mph. 3 HP should get it to hull speed though, not much more.
June 16, 2015 at 2:56 am #18181
david-bartlett
Participant
Cory,

I’m with Frank on this one. Sounds like you have a 1 cylinder Lightwin.

Here is a video of my JW(same motor essentially) running in a bucket. About 45 seconds in I rev it up some, but not all the way, and even that much seems to be running stronger than yours but it is hard to say from videos.

Anyway, Welcome, and enjoy your motor.
June 16, 2015 at 1:29 pm #18191
fleetwin
Participant
US Member - 2 Years
I was jumping the gun too, I think Frank is right, only running on one cylinder. Possible bad plug or ignition.
Next, I would have a look at the throttle cam. Sometimes the carb linkage gets stuck and just bends the cam back when you try to advance the throttle.
And yeah, don’t try to remove the high speed jet without the correct tool: OMC 317002, you will mess up the jet and the bowl. But, I’m thinking the engine would have just faltered and stalled out if it was too lean. But, I guess someone could have messed with the jet or replaced it with a larger one causing it to run too rich.
Finally, sure looks like someone has jammed the wrong low speed needle in the carb, but that shouldn’t really affect the high speed too much.
And yes, you can usually sneak the tank out of the bracket with the fuel valve still in place.
June 16, 2015 at 2:16 pm #18195
corythecowboy
Participant
Neither my Dad or I are mechanics, but it certainly looks like it’s only running on one cylinder

https://www.youtube.com/watch?v=iBdrioF … e=youtu.be

Cory
June 16, 2015 at 2:35 pm #18196
The Boat House
Participant
- This reply was modified 6 years ago by The Boat House.
- This reply was modified 3 years, 9 months ago by The Boat House.
June 16, 2015 at 3:23 pm #18199
crosbyman
Participant
Canada Member - 2 Years
you did open the vent ?

tried openning the gas cap.. if it runs better the 2 vent holes Under the scrw vent are crudded up …look closely to find 2 holes..
open them up with a paper clip or small wire

Joining AOMCI has priviledges 🙂
June 16, 2015 at 4:27 pm #18204
corythecowboy
Participant
quote crosbyman:

you did open the vent ?

tried openning the gas cap.. if it runs better the 2 vent holes Under the scrw vent are crudded up …look closely to find 2 holes..
open them up with a paper clip or small wire

Vent is open and the two holes are clear. Thanks for that though 🙂

Cory
June 16, 2015 at 4:54 pm #18206
fleetwin
Participant
US Member - 2 Years
Yeah, so much for the simple solution, seems to sound stronger in the tank than on the boat, but seems to be running on both cylinders.
RPM seems pretty high, but not much thrust coming from prop in the tank. Is the prop in good shape, shear pin and rubber prop hub OK?
Doesn’t idle worth a fart, but that may be due to what looks to be the wrong needle valve jammed into the carb.
Have you done a compression test? Sounds like it has an exhaust leak (leaky exhaust cover?) as well.
Again, seems to wind up, so I don’t think the high speed jet is partially plugged, would probably just bog and die if that were the case. Doesn’t sound rich either, but anything is possible.
Just thought of something. Is this a lightwin or a yachtwin? A yachtwin has a right angle drive propeller, someone may have put a yachtwin gearcase on this engine with the larger pitch 5hp prop which the 3hp could never spin up.
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