Evinrude 10 XP uppgrade to 15HP

raczekp1

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I got Evinrude 10 XP with restrictor plate removed.
rebuilt the carb( new plastic top cover)
compression is 8 bar in lower cylinder and 8.5 in upper.spark plugs are ok, spark ok.
motor with UFI ignition( cdi under flywheel)
i tested motor on the boat and i cant plain the boat.
i could do it with 8 hp
prop hub is in the place
 

Sea Rider

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Sep 20, 2008
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Don't know about that model, use to have a EVi 9.9, to fully convert it to a 15 HP needed to change the complete reed valve assy, gaskets and the carb to allow more fuel in. Keep in mind that a 15 HP carb has wider fuel passages, so swapping 15 parts onto a 10 HP carb won't do a thing, engine will not deliver it's real converted HP.

Happy Boating
 

oldboat1

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Dunno. The boat appears to me to be on plane. (Wake looks like what you would expect at speed.)

Idle speed setting might be a little low, but engine seems to be nice and smooth.

Maybe could be raised slightly on transom, or weight could be shifted forward.
 

Sea Rider

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Check if the timing advance and carb synch are same for both models and if carb codes differes, if so, change carb. Afterwords can install an induction tach to check max wot rpm achieved with current prop as loaded, probably rpm is way low from factory specs into lugging territory

Afterwords can go for a prop maximization for OB to rev middle to max wot range as loaded, if wanting near instant plane prop OB to rev to its max factory wot range with a less pitch prop if you're 100% sure conversion has been done spot on. If not it's a waste of time rising, lowering OB on transom, playing with trim and weight distribution..

Happy Boating
 

Chinewalker

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Not planing the boat? Looks to me like you're flat out flying! Motor sounds good through full range. Not sure what you're expecting, but it sure sounds like it's running okay to me.
 

David Young

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I agree on what others are saying. That thing is hauling butt, for what it is :)
 

Stumpalump

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An Evinrude 10 was a very cool oddball motor. Instead of just selling a 9.9 they took a 15 and added a restrictor plate. He took the plate out so it's got all the 15 hardware like carb and exhaust tuner. I agree that the video shows a pretty good sounding motor but if Evinrude reduced the size of the main jet to match the reduced flow of the restrictor plate (and that would make sense) then the first place I'd look to get a bump in top end is what size jet is in it and is it the same jet used in the 15 hp. Geeze that was a long sentence....
 

jimmbo

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A bigger jet would just richen the mix, more air is also needed, so the 15 would also have a higher CFM carbi, jetted for its expected airflow
 

raczekp1

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here is movie from today.
i trol 10 min and notice suel floating around midsection.
checked no fuel lik from fuellines.
so carb is geting to much fuel.
after troling i did hole shot.
in the begining motor cant catch high rpm, propably to much fuel residues in crank case
look at the begining of the move:

https://www.youtube.com/watch?v=lLeo...ature=youtu.be

but after 20 sec or so motor catch good rpm.
 

oldboat1

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May be all wrong, but think I'm seeing a little bit of porpoising -- might move some weight forward, or maybe change the trim to a more tucked position. Seem to see the porpoising at about 26/27 sec, just before you throttle down. Also seems to be pronounced at about 1:22 and 2:17-2:24, again just before throttling back.

Also might check to be sure the tilt lever is in the locked down position for running.

Other than that -- how is the fuel pump? Not really seeing much in the way of operational problems, but if it feels wonky before it seems to lean out and accelerate, might need a fuel pump diaphragm. (Might account for what appears to be excess exhaust after throttling down -- guessing here, as that may be normal after throttling down quickly.)
 
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raczekp1

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will check fuel pump squere diaphram( lower one) but i think the problem is float needle or gaskets under main nozle.
motor is geting to much fuel for sure
 

jimmbo

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Watching the video, the engine does seem to accelerate slowly, but steadily. At some point it starts picking up like it hitting a sweet spot in the torque curve. You have modified the 10hp by removing a restrictor plate. Did the engine behave like this prior to the removal?
Is the carb still the 10hp carb, or is it a 15hp carb? What else may be different between the two engines? Reeds? Reed Stops? Anything on the exhaust side? There can be other difference too like heads, and piston too. Same displacement often does not mean same engine with a different carb.
 

raczekp1

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fuel pump diaphram is ok, no holes.
i could comper oriface plug in carb
0324025 dia is 0.8 mm and its for 9.9 hp carb
and 0334014 dia is 1.3 mm and its for 15 hp
changed carb need and will try outboard performance
 

Stumpalump

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fuel pump diaphram is ok, no holes.
i could comper oriface plug in carb
0324025 dia is 0.8 mm and its for 9.9 hp carb
and 0334014 dia is 1.3 mm and its for 15 hp
changed carb need and will try outboard performance

There you go. ^^^ If you want to verify that that is the only problem (and it is) then put the restrictor back in to see if it runs nice. Your motor is the holy grail of the 9.9/15hp of that vintage. A lot of lakes are 10hp maximum here and you already have everthing a 15 has except for the jet and restrictor plate. And of course decals that say 10. You have the big bore carb, the reed spacer and exhaust tuner of the 15 already in there. I've never seen one in the United States of America so consider yourself lucky to have one. Please keep us posted.
 
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