1972 hydro-electric Fuel line size?

Paulywog0667

Petty Officer 2nd Class
Joined
Aug 5, 2017
Messages
139
Does one of the fuel lines coming off the fuel pump on a 1972 Johnson hydro-electric 50hp need to be 5/16" and one 3/8" or can both be 3/8"? It starts, but keeps shutting off.

I replaced my old power pack after it started, but wouldn't restart. Not certain if I have a short or just fuel issues. After replacing the power pack it starts right up, but won't stay runnin .
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Putting a 3/8" hose on a fitting that is made for a 5/16" hose, is just asking for leaks.

Does it run for a few seconds, or quit the instant you let go of the key?
Describe your starting routine...
 

Paulywog0667

Petty Officer 2nd Class
Joined
Aug 5, 2017
Messages
139
Runs for a few seconds. I primed the fuel line bulb, turned the key and it ran. After a few seconds it shut off and then I could restart it without priming, but it would run less. Then nothing. I lost power to the plug and swapped out the power pack and now starts again, but not a fan of guessing a short or just need to clean the carbs.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Guessing what is wrong and throwing parts may eventually solve the problem, but will get very expensive. It would appear to be a fuel starvation issue.But first, what is the choke set to, Off, Auto, On? Are you using the Warm up Lever? Is the primer Bulb collapsing?

Can the spark jump a 7/16" gap.
Have you dome a Compression Test?

The Primer Bulb really should only be needed if the carb fuel bowl is low/empty. The bowl will empty if the fuel supply runs out or is starved, the engine is tilted up and the fuel spill out of the carb, or there is a leaky fuel bowl.
You might have a leaky fuel line, a weak or bad fuel pump, blockage in the fuel system, including the tank
 

Paulywog0667

Petty Officer 2nd Class
Joined
Aug 5, 2017
Messages
139
I was debating the carb. I replaced the ignition switch and only have it on a cheap pull switch. I usually leave it off and use the manual knob while testing. If the carb I'd guess some laquer showed up at the needles from sitting. The only thing that isn't new would be the stator feeding the powerpack. Since oddly I had a new used powerpack and after starting the outboard, it had to go on after losing spark. Coincidence has me guessing, but 1972 is starting to run a little shy on powerpacks. Lol

The fuel pump was old and got replaced, but not keen on the universal replacement. When I replaced the fuel lines, I grabbed just 3/8" and 3/16" (carb connector). I did have to upgrade the hose clamps to prevent leaks and tape a fuel pump nipple thread. That got it firing right up, but it doesn't stay running. I wasn't certain if one of the lines for the fuel pump is supposed to be 5/16" instead of 3/8".
 
Last edited:

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
For many years the 5/16" line/hose was it, When the 200 V6 was introduced for the 1976 model year, the Fuel Line/hose for it and all the later V6s was increased to 3/8".
 

Paulywog0667

Petty Officer 2nd Class
Joined
Aug 5, 2017
Messages
139
I got it started. A fuel line clamp was loose and needed to put a heavier charger on the battery. Should be able to tune the carbs and put voltage to the shift solenoids tomorrow.
 
Top