MODIFIED 9.9hp to 15hp Johnson Outboard Conversion - TEST RUN!

[@rickparker5437]

I have bought, sold, repaired small boat motors for 40 years. The 1980 15hp Johnson, is the best motor ive ever had. Fast, quiet, well made, and most of all dependable.

[@MONEYBAGS603]

i have a johnson 15 1975 and my motor does not pee out the tail tail. when i run the motor the head seems to stay cool. are these motors suppost to pee water?

[@rickparker5437]

It should have a steady stream. must have something clogged up. sounds like impeller is working. But need to get that problem fixed

[@igotmesothelioma]

MONEYBAGS603 the 75 didn't have a tell tale. Should see it out of the exhaust port

[@EnginesandElbowGrease]

Thanks man! Our lake where our camp is has no limit because it has an end to end lake of about 15 miles. And a huge circumference. Our motor was stored in the basement at our house, so no mud wasps, although I believe we have those up here as well. Thanks for the advice!

[@davshaw5]

Put your hand over the exhaust where it comes out of the prop when running it on muffs. This will create suction and will then pump water out the telltale. Have to do this with my 76 Johnson 15.

[@Dantheman_88]

Dude you need to add the tuned exhaust to that thing to get the full performance out of that carburetor.

[@jamescooper4167]

The water inlet holes for the water pump are the ones on the top and it's hard to get muffs over them it's best to use a barrel or large bucket.

[@bsrktm1]

The water tube can be very hard to get into the pump outlet on these engines. You may have missed it- done it myself. Later engines used a taller grommet to make it easier to align everything, Good luck.

[@gorillacookies3451]

Reed spacer and tuned exhaust were also used on the 15hp. So not just carb jetting to go from 9.9 to 15hp

[@EnginesandElbowGrease]

I think it's the thermostat since we replaced the impeller last fall and it worked fine.

[@EnginesandElbowGrease]

Yeah, all boat motors come out there and usually a side port as well.

[@157bradley1]

I have the exact same motor with a 15hp carb too. We have a local lake with a 10hp legal limit, so the carb is a 'cheater'. Anyway, I have never had much luck with muffs on that motor. Try it in a trash can full of water or something similar before you tear in to it. Also, down here in Alabama, 'mud wasps' are bad to build in exhaust holes of you leave the motor where they can get to it. Just a couple of thoughts. Keep up the vids man,

[@davkrat5]

My 1977 15hp Evinrude does the exact same thing when it's on the muffs. Does not pee out the indicator for quite some time at idle but the heads do not get overly warm. It doesn't blow steam and when the thermostat finally opens the stream is warm at first but very quickly cools. On the lake with the lower unit submerged it pees water instantly. I think it's just what happens with the motor on muffs, impeller pumps water out through the other holes in the body until the thermostat opens.

[@denniskhan7748]

Hi I had the same issue with my 9.9 at first which worked fine out on the water in the boat but pumped very little if not any water with the muffs through the tele tale but resolved this with a little bit of Kiwi inginuity with just a simple plastic medium size syringe and warm fresh water whilst flushing after use back squirting through the tele tail while engine were stopped with muffs on and then starting again a series of times which improved the flow dramatically and helps dissolve any build up of salt or calcium which I think is the cause of such.

[@ct1762]

just so you know the 81' and up i believe had the bigger wider round exhaust , these still had the narrower rectangle one. the exhaust makes a big difference in the midrange!

[@dewaynemarcionette6112]

The exhaust was tuned as well

[@silverstarflite135]

Would it not be better to start it in neutral?

[@mrsuarez430]

Alan Rothfuss mine doesnt even let you start if its not on neutral

[@francisebikedriscoll847]

It was in neutral

[@rm42749]

Nice boots!

[@james258063]

Nice I love your boat videos

[@mrsuarez430]

Sounds like its knocking a tad ? Mine sounds completely different

[@TheMrRuger]

Crazy enough to work I think.

[@1997cr80r]

If you look at my videos I did a pee hole water indicator port thing mod on my 1968 Evinrude 6hp, it's probably a sheared key or bad pump, take off the thermostat cover and take the stat out and start it in a barrel of water and see if it pushes water out where the thermostat was

[@EnginesandElbowGrease]

I plan to.

[@EnginesandElbowGrease]

Oh sweet!

[@ronzogo]

With out tuned exhaust it will run rich

[@outlawlilly]

Nice. Fried that one.

[@tpainter81]

Muffs won’t cause enough pressure for it to pee water. Got to do it in a tank.

[@EnginesandElbowGrease]

I'm gonna try it in the water soon I think.

[@denniskhan7748]

Hi Ive got a 9.9 myself and thought to actually get the full benefit of the upgrade to a 15hp Johnson a manifold exchange were in need as well which could explain why she's not running too great being out of tune, It has previously crossed my mind to do the same though as well but from what Ive found with a little bit of research prefer the notion of having a flawless and sound motor that starts first time every time over a little temperamental extra out of tune grunt, Good luck with sorting anyways but personally if thats the best you can get it to run Id swap it back to how it were originally to begin with and look at selling and upgrading to a good running 15hp to begin with

[@MrLupold]

yes it would!

[@carrysmith2008]

so by putting a bigger carb.that motor went from a 9.9hp to a 15hp?? thats a big increase with just a carb.

[@EnginesandElbowGrease]

Yeah, I'm gonna try just throwing it on the boat and in the lake.

[@aphoticontario2645]

need to tap into the side and make a pee stream, did it myself never looked back.

[@THEMOWERMEDIC1]

Carb is loading up please fix

[@KeystoneMotorsports]

Thats cool how the exhaust comes out by the propeller. But then again, I dont know shit about boats so most of them probably do that haha.

[@EnginesandElbowGrease]

There will be more soon!

[@EnginesandElbowGrease]

Crazy enough that we just need to put it in the water and try it? Haha

[@imonone325]

I have a 6 hp one just like that but it won't spark.........I have to adjust the points

[@bluegas101]

I'm guessing this boat doesn't have a water pee hole.

[@jaker805]

Salvador Garcia these didn't, the water is pumped out with the exhaust. you can kinda see it if you watch the prop

[@motorizedeverything]

I have a 79 sears Ted Willams 9.9hp

[@fleetwin1]

OK, well that engine appears to be cooling normally on the flushette. There is no water spray from those early models out of the upper relief hole until the thermostat opens...Try it on the boat to be sure...So, what I see in your video is normal for that engine. On a more important note, the exhaust noise changed tune when the engine started to load up, might have even been running on just one cylinder...Better check compression again to make sure head gasket isn't leaking... Look at the plugs for water droplets... If the compression is OK, and no water evident on plugs, try it on the boat in the water...These engines can definitely get fussy when trying to cool em on the flushette...

[@hucknbarry3496]

Maybe water pump didn't get primed

[@TheDrCoxie]

To make it a true 15 hp you need to put the modified exhaust on it

[@TheDrCoxie]

Also sounds like its surging a bit which means it needs crank case seals and the cooling is probably because the grommets under the engine have swelled up and are restricting the water flow. All that means a set of power head seals and caskets (youll want to lift the cylinder head while youre at it) as well as new grommets for the water pipes. Full engine rebuild in other words.

[@PappyfromtheKeys]

Incorrect. That vintage 9.9 used the standard exhaust pipe, small carb, and standard reeds. The 15hp engine of the same year utilized a larger (15hp) carburetor, a tuned exhaust pipe, and had a spacer under the reeds from the factory. Look it up in any parts book.

[@danielmcginn2120]

not pumping water

ooohhh very good

[@technologyguy101]

Should not have started in gear, sure was hard on the starter the way he pulled it, no water from telltale, sure was restrained when asked about lower unit...interesting.

[@gurnblanstein466]

Probably has a bad impeller.. Rebuilt lower unit mhmm...

[@graemestephens1894]

Not working dude. fix it first before going out.

[@outboardfun3353]

The 15hp has turned exhaust pipe that the 9.9 does not have so you aren't getting it to 15hp with out changing the turn pipe. you may 11or 12hp You would do better to change the exhaust pipe on the 9.9hp

[@iixlegitgamer]

Ya it's better to run them in water. I have a brand new merc 9.9

[@Datsun280zeeee]

Get a big buket

[@Datsun280zeeee]

Dont use that hose thing. The impeller is supposed to SUCK THE WATER BY ITSELF, not the hose forcing water up in it