1978 johnson 15 hp lots of smoke

[scott613]

hey guys first time on this forum .
i came across this by surching some answers and btw great job guys . this site awsome .

sorry for this being a long post .

ok to the problem im having .
now i just got this moter and i went over it before i started it .
it sat for a long long time .
i got it running . with fresh gas. and 5 pulls .

now while its running no matter what rmp im at .
i get alot of smoke . i know 2 strokes do smoke but its more then usual .
the gas is mixed right . as per dealer
now when i had it in the barrel and running . in gear or out of gear , its smoken hevey . and when the top part of the moter ( shell ) is on . the smoke is chocking out the moter . i cant even get anything out of her . just bogs right down . and eventually die's .
i take the shell off and away it goes again . but it looks like from what and where i can see is its smoke from just under the carb . and like i said it hard heavy smoke . i took the lil breather box out . and ran it again . to see if my theary is right and yes its under the carb . (but not from the carb ) by the moter part .
i checked the plugs . it seems to be burning ok . and i can get full rpm . with shell off .
but with shell on . about 8 secs before it chockes itself right out again .
at idle . its smoken hard as well .
the lean and rich dont do anything . (it does but not with the smoke)
now . is it possible it could use a really good run (couple houre tour)
and bring a spare moter just incase ? lol . or is the gas mixed really to rich .
the michanic here told me for 20 liters of fuel . one 250 ml bottle for the 20 leters . so he said thats 50:1
so i said ok cool . now . in the barrel .
there was alot of oil . floating in the water . after it settled .
another thing . i dont know if this is the cause . but . the lil peeing line. thats supposed to pee out water . isnt doing it .
i took the line out and cleared it out . and still nothing .
but . there is alot of water comming out of the middle of the bottom end where its supposed to be . so i know the water pump is working . so maybe clogged some where ? .
and and if dont fix itself from a long tour . will that hurt the moter . ?
i held my hand on it . and i had about 10 secconds i could hold my hard on it before it couldnt no more . so its getting nicely cooled .

so any ideas?

again . sorry for the long post .

 

[Daviet]

Re: 1978 johnson 15 hp lots of smoke

It sounds like you have a blown power head gasket allowing exhaust to exit between the power head and the exhaust housing.
You could leave the cover off and put it in the water and run it at WOT for a while and see if the smoke problem gets better.
Sounds like your tell-tale might be plugged, remove the hose where it attaches to the block and run it, if it squirts the problem is a clogged hose.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

yeah i jsut did that actually .
i took the hose off . and it was able to blow threw it with out a problem .
could the problem be some where els ?

 

[Daviet]

Re: 1978 johnson 15 hp lots of smoke

The tell-tale is an indicator of water pump operation. If the engine is not overheating and you are not getting water out of the tell-tale check the fitting in the block and see if it is plugged.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

ok just did . that .
now i couldnt really tell if its plugged or not .
but i did huck up a longer hose to it .
and i couldnt blow threw it .
now could that mean . its plugged some where els in the moter . ?
and if so .
so i take my garages air line . and blow 120- 150 lbs to air into it . and see it it would blow back out the other end . if its the problem ?

and for the smoke issue ? is that a hard fix ? are could i jsutdrive it like that? lol .

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

or would that much air hurt something ?

 

[Daviet]

Re: 1978 johnson 15 hp lots of smoke

Take the fitting out of the block and check it with air pressure. While the fitting is out look in the hole for blockage or crank the engine up and see if water comes out.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

ok will do . tomorrow .
when i got time . prolly tomorrow morning .
now . is there anything els i could do to this ? before i take her out in the water tomorrow . and not worry about it ? (moter wise )

 

[Daviet]

Re: 1978 johnson 15 hp lots of smoke

You could take a test run but you are going to have to give some attention to the power head gasket and carb, rich lean makes no difference, in the near future.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

yeah . i wonder if it just needs to be tightned down again ?
like i said . it sat for a long time .
or should i jsut say screw it . and after a nice run if it dont improve . to take the carb off . and take the part off and get a new gasket for it . or use gasket maker ? .

 

[Daviet]

Re: 1978 johnson 15 hp lots of smoke

Remove the carb and overhaul it using a carb kit. If the power head gasket is blown, remove the power head and install a new gasket.
When working on outboard engines it pays to do the job properly the first time.

 

[bktheking]

Re: 1978 johnson 15 hp lots of smoke

If its the powerhead base gasket, replace it, remove the powerhead and buy a gasket. You could try tightening the 6 bolts at the bottom of the lower cowl but I doubt it will help. Why say screw it, there is probably more that needs replacing, upper water tube grommet, possibly the lower crank seal, lots of opportunity to make it right once the powerhead is off.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

so true guys .
and this moter here is the first moter i have ever had trouble with lol .

like i have a very old mint condition viking moter . 6 horse .
mint sheel . paint is on the moter is still nicly painted green with no scatches .
same spark plugs that came with the moter .
origonal prop.
everything is mint .
it has les then im thinking 100 hours on it as . my grandfather gave it to me ,
he stored it in the closet its whole life basicly lol.
i use that one for a nice ol cruise from time to time .
but ill do the things u guys sudjested .
but as i just looked at the setup . ;p
its going to be fun getting the carb off . and then trying to get the pull cord off .
there got to be a trick to it all .
i jsut might have to bend a nice old wrench . the opened end to get the nutts off the carb on the pull cord side . ?
correct guy ??
and thank you guys for the advice . already im learing alot .

 

[bktheking]

Re: 1978 johnson 15 hp lots of smoke

This is what I do: Undo the bolt out of the recoil but don't pull the bolt out, then I wrap the entire recoil a couple of times with electrical tape to keep it from coming apart, this will allow access to the right side of the carb. Make sure when you put the starter back on that the tab on the bottom of the cup goes into the recess beside the hole for the starter bolt, you'll see what i'm talking about once its off.

 

[scott613]

Re: 1978 johnson 15 hp lots of smoke

you guys are a big help .
thank you so much .
ill keep you guys posted what happends when the gasket comes
in .
once again
thanks
scott .