Re: Johnson 48 spl can it be saved?

[tashasdaddy]

Re: Johnson 48 spl can it be saved?

see further down, something strange happened when i merged the threads.


not holding prime is an air leak in the fuel system. probably a leaking connection. which could cause your idle problem, air leaking into the system, the compression is a little off, but not terribly.

 

[floatingwoody2006]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

Those compression numbers are fine, and when you get the carbs re-built and it runs well, running more sea foam thru it may well equalize those readings. Definately do the carbs..It's cheap enough to do, and gives you a winter project.

 

[samo_ott]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

And to answer your question, virtually all engines are worth saving

 

[navrivr]

Uneven Compression 48spl

Uneven Compression 48spl

Hello,
Here it is I have a 1987 48 spl , it has idled roughly last 2 seasons,
I use this motor every weekend. It has always ran smoothe and very
strong a med to high throttle.
Mechanically motor is fine.
My question is after reading forums on rough idle's I did a very thorough decarb with Sea-Foam, this helped somewhat.
The motor has all the classic symptoms of a carb. re-build spitting carbs and
not able to hold prime.
after Sea-Foam it now holds prime.
I checked compression cold prior to decarb.
top check 160 bottom checked 150, after decarb re-checked compression with motor at operating temp. top 145 bottom 130.
My concern here is the Seloc repair manual states that compression should be within 5 lbs. of each cylinder.
Most Threads I have read state within 10% of each other.
Is the 15 lbs, difference in the cylinders to much to warrant re-building carbs or what ever else needs to be done to smoothe idle.
I can't seem to sync and lync with my carbs in such a poor condition, also will
the compression difference I have inhibit the motor to perform as it should?
e.g. Idle smoothely , hold idle(maintane) , hold prime.
The only reason I would like to save this motor is it still runs fine a open trottle and other than rough idle this motor has always been a very strong runner.
Any help and advice will be greatly appreciate.

Thanks !

Navrivr

Hello,

1987 48 spl Top = 145 ; Bot = 130
Did a very thorough De-Carb with Sea-Foam.
I talked to a local Dealer / Mechanic about the compression and possible
repairs.
His Opinion is the Compression should be more even, and suspects worn rings
or leaking Head - Gasket.
I would like some other input from others who have experience with thier
outboards and any Compression issues.
I would like to know if this motor can be serviced, carb-rebuilds,and all other
related repairs with the uneven compression 145 / 130 condition.
I would like to do the work myself , to gain further knowledge of outboard motors.
These Forums are a Great way of obtain knowledge and experience from others.
Any input or help is greatly appreciated.

Thanks!!
Navrivr

 

[tashasdaddy]

Re: Uneven Compression 48spl

Re: Uneven Compression 48spl

please keep your post together.

 

[mikesea]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

compression is not the problem,you may have not cleaned the carb passages and idle speed is being effected,or,you say you cant get the synic link right,that is a very important part ,especially for idle,dont understand why you cant get it right?you should have and adjustment screw on one carb that allows you to close both butterfliesthen re-tightining the set screw.then set the roller,if you dont have a book,someone may have posted alreay the procedure,do a search,that all said,the only time ?I ever had a sync link prob,was the butterfly rod was worn out to the point it wobbled just enough to be troublesome,then needed to get used carbs

 

[navrivr]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

I have not ever serviced the carbs. ( 20 yrs.)
they have never been off motor, I only fogged motor each winter.
Motor was serviced for water pumps 3x.
I have a Seloc Service manual.
Tried sync and Lync with the adjustment screws you described. , just could not get even idle.
The butterfly rod you described is loose and wobbly, I will check that tonite.
I suspect that after 20yrs the carbs are in very bad shape (internally).
I will let you know when I open them up.
Thanks for info on throttle butterfly-rod, sounds like I'll need to remedy that,
when I do my carb. re-builds.

Thanks!!

Navrivr

 

[HighTrim]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

20 year old gummed up carbs, yikes! I feel guilty when I go 3.

 

[DJ]

Re: Johnson 48 spl can it be saved?

Re: Johnson 48 spl can it be saved?

20 year old gummed up carbs, yikes! I feel guilty when I go 3.

Agreed. With todays fuels, it's a whole new ballgame. It may be yearly, from now on.