Problem with 1989 Johnson 48 SPL

[spencerhmoore]

I just bought this engine. Initially, it would start, rev up to pretty high RPMs, then lose RPMs and die. I disassembled, cleaned and rebuilt both carbs. Compression is 140 top, 150 bottom.

After the carb rebuild it wouldn't start at all. Turns over fine, puts smoke out the back, shooting water out strongly, just won't start. After I did the compression test it started with the same symptoms as before the rebuild, then died. Won't start again unless I remove plugs and turn over briefly. When I put the plugs back in it'll do the same thing.

Plugs are pretty clean. When I take them out they are wet.

Ideas on how to proceed?

 

[tashasdaddy]

Re: Problem with 1989 Johnson 48 SPL

did you remove the jets? set float properly? sounds like it is flooding. http://forums.iboats.com/showthread.php?t=244013

have you done a link n sinc? that is a great motor.

 

[kenmyfam]

Re: Problem with 1989 Johnson 48 SPL

Sure sounds like flooding, however have you checked the spark ??

 

[spencerhmoore]

Re: Problem with 1989 Johnson 48 SPL

I have not replaced the jets. Next I will check the spark and do a link & sync; I'll let you all know the results.

Thanks for your advice.

Spencer

 

[tashasdaddy]

Re: Problem with 1989 Johnson 48 SPL

know need to replace jets, just clean them.

 

[spencerhmoore]

Re: Problem with 1989 Johnson 48 SPL

Here's what I've done so far:

1. Cleaned and rebuilt carbs as mentioned above.

2. Replaced fuel pump (probably not necessary but not too expensive and now I've got a spare)

3. Replaced all fuel lines, including lines to and from choke primer solenoid. I had previously noticed bits of black material in the carbs; I think they were bits of rubber from a degrading fuel line.

4. Replaced the disposable fuel filter between the incoming fuel line and the fuel pump.

5. Replaced the cap and gasket to the choke primer solenoid after I broke one of the nipples trying to get one of the small outbound fuel lines off of it.

6. Bought the Clymer shop manual (this is a good manual, with good coverage specific to my motor) off Ebay.

7. Did the linkage and synchronization (link & sync) as specified in the manual, as much as I could do in my driveway with a barrel. Not very hard to do. The previous settings were way off.

Now the motor idles in neutral, albeit a little roughly. Way better than when I bought it.

Next step is to do some at-the-dock testing (setting the idle correctly) and then some on-the-water testing. I suspect this testing will either go well or perhaps will amplify the roughness I get at idle. We'll see.

It's been an adventure so far for a neophyte mechanic and my 12 year old son. I'll let you all know how it ultimately turns out.

Spencer