1990 50hp johnson sputter under load

[22E6441]

Was out today with the boat, ran great. Had 4 adults and two little kids...ran full power for about an hour...perfect. Took it out again slower and putting around a bit. Perfect.

Took it out with just me in it and went full tilt and did some turns...all of a sudden it started sputtering or misfiring. Slowed down and it seemed to run perfect again. Gave it some throttle and it started to go, and then started sputtering again before I could get on plane....could not get on plane at all.

Starts fine.

Idles fine.

Drives at slow speed fine.

Drop the hammer and it sputters.

I popped my engine cover and it looks like my lower carb has a bit of gas/oil outside of it like there was a bit of a leak or something. Just a bit though. My engine compartment was spotless before. This is just like a misting though...not like full drops or puddles or anything.

What up?

some other posts make it look like maybe this is just a card thing. Remove, clean, install new carb kit and should be golden. However, the other posts I saw were smaller motors. One was a 9.9 and another was a 6.

What do you guys think?

 

[tashasdaddy]

Re: 1990 50hp johnson sputter under load

no alarms, you probably picked up some trash in the lower carb. see the TOP SECRET FILE, carb cleaning. you are due for new fuel lines, be sure to use alcohol resistant lines. (Ethanol)

 

[22E6441]

Re: 1990 50hp johnson sputter under load

Thanks, TD. I feel better now.

Between the secret file and my Seloc manual I should be able pull off a cleaning.

I've never tried anything like this before, but I figure I'm handy enough for it.

Now, where did this debris come from? Should I discard the fuel in my tank and spply line from the tank to the motor? Or is that overkill?

 

[tashasdaddy]

Re: 1990 50hp johnson sputter under load

the old hoses are effected by Ethanol, the interior gets soft, and sluffs off, getting into the bottom of the carb bowls, and then blocking the fuel pickups. you are due for fuel lines anyway, so use alcohol resistant lines. if you tank to motor does not say alcohol resistant on it replace it also. you can just cut the ends and bulb, and make a line, use 3/8 inch line.

 

[22E6441]

Re: 1990 50hp johnson sputter under load

OK, I've got carb kit (sierra 18-7222 with float), and I've read the carb cleaning thread.

I'm still much more nervous than I should be about this, but I'm going to start tackling this later today.

Questions before I get started:

1) I don't have the special screwdriver tool or a grinder to make one. I'm still not sure exactly what it's for or why I need it. More info would be appreciated, and if there are any work arounds, etc.

2) So I'll try not to disturb any of the linkages, etc. So long as I follow all the directions and don't disturb anything, this should be a quick project, right? Or am I going to be stuck trying to turn adjustment screws on two carbs trying to get it perfect?

3) As for the gas lines, what size and length should I get?

4) I need to buy some carb cleaner. Is it crucial to let it sit overnight, or should a couple hours be sufficient?

5) I don't have a compressor. Would those cans of compressed air br OK to use? You know...the kind for blowing junk out of keyboards, etc.

Once I start tackling this project, I will be taking tonnes of pictures and posting everything here.

 

[tashasdaddy]

Re: 1990 50hp johnson sputter under load

the 4 in 1 screw driver sets has a small tip that will fit, just becareful not damage the slot. you are 100% on the right track.

 

[22E6441]

Re: 1990 50hp johnson sputter under load

Please close this thread.

New summary set up here:

http://forums.iboats.com/showthread.php?p=2250986#post2250986