56 15 hp fuel system

[Max_Door]

Hello, Thanks to you guys, I got this old Johnson motor to run pretty good. But I can't seem to get it to idle down as far as I think it should. The high speed needle seems set fine, and it runs good at high and midrange, but when I try to sit and idle or run at trolling speed, it spits and pops and eventually dies, unless I run it at slightly faster than I think is trolling speed or idle speed. <br />I have tried to dial in the slow speed needle but it is just not getting down to smooth idle speed. <br />I can sometimes hear the slightest hissing at the fuel line connector, could that be all that is wrong? One other thing, this first tank of fuel was mixed pretty heavy on oil, could that have something to do with it too?

 

[Max_Door]

Re: 56 15 hp fuel system

I forgot to mention that I did clean and rebuild the carb, think I did it right, checked the float, cleaned all the passages, etc.

 

[cajun555]

Re: 56 15 hp fuel system

Max, sounds like you still have the old 2 line setup. If your hearing a hissing sound you must be loosing air pressure somewhere from power head to the tank. If you loose enuff pressure at idle then you will starve carb for fuel and it will run like a lean mixture. See if you can correct the air leak, then readjust the low speed needle. The way I adjust my 56 30 hp is to back out untill motor smooths out then slowly turn back in un till it coughs then back the neddle back out till it smooths out. Make sure the pasking nut is toght enuff that the neddle can't turn by it self. Good luck.

 

[steelespike]

Re: 56 15 hp fuel system

Spitting and popping is a lean fuel problem.<br />Not likely to be from the high speed but when adjusting it make it just a touch toward rich from the best setting.This will insure it gets enough lube at high speed and will insure it is not set too lean.I assume you have tried to adjust the low speed with the linkage unhooked so you can get a full turn.<br />There could be an air leak, possibly the crank seal.Also look for leaks at the crankcase and carb flange,reed block etc.It could suck air from the air hose hook up.You should fix the leak.Possibly just needs a new o ring.Be sure you have a good strong spark as a weak spark sometimes causes sneezing and popping.Usually<br />it will cause poor starting and performance too.<br />Forgot to mention I dont think your fuel mix is the problem just be sure fuel is fresh and plugs are not fouled.

 

[Max_Door]

Re: 56 15 hp fuel system

Thanks, I will fix the leak I sometimes hear at the fuel hose hook-up, hopefully that is causing the leaning-out.

 

[Paul Moir]

Re: 56 15 hp fuel system

Max_Door:<br /><br />Dual line connector rebuilding discussion, click here.<br /><br />The O-Rings are part number 301824. They're metric (5mm ID x 3mm wide) so they're not a hardware store item. Unless you've got a really good hardware store.

 

[alcan]

Re: 56 15 hp fuel system

Hi Max<br />After you resolve your leak problem. The connector being the most suspect, and they usually are. Remember that the throtle plate (butterfly) has to be fully closed in order to adjust the low speed needle properly. You may need to back off any idle speed stop device.