1973 4 horse johnson

[hobojoe]

hi you all helped me with my brothers motor back in nov so lets hope you can help again..we replaced the fuel pump now motor wont stay running.sometimes does sometimes not.and to start it have to turn top dial (not sure what it is)say slow speed under it. sometimes have to turn the lean/rich.ive got it as of comming home to where i can can start on 3 or 4 pulls it smokes real bad. we dont have a manual what is the dial above the lean/rich and any spacific setting on it? also we replaced the impeller last year how much water should be spraying out the back it has 4 little holes on each side and can see a little spittle coming out. i had a 30 merc years ago and shot a stream out.and not sure if just a spittle is all it should be getting or not. i think this is a 4r73c johnson its at bros house so cant look.hes leagally blind and an amputee i am unemployed so cant afford to get a manual.and of course that motor you cant download for free..we appreciate any help we can get thanks. joe/mike

 

[lindy46]

Re: 1973 4 horse johnson

The slow speed needle should be opened about 1.5 turns to start. Will it keep running if you squeeze the fuel line bulb? You won't see a stream of water on that motor - just a spritz out of the small holes.

 

[Davem3]

Re: 1973 4 horse johnson

and for giggles, the whole water pump would be a great idea, the new ones have a stainless steel insert that works wonders, a new thermostat would help as well............ on the making it run

like Lindy said, set the slow speed needle CAREFULLY all the way down, then back off 1.5 turns

i am thinking replace all of the fuel lines, question the fuel pump,and try decarbing the engine if possible to keep it running long enough. It is possible that the carb might need a rebuild, but go one step at a time............

50:1 oil/fuel mixture and check the spark as well............

if needed pull the flywhell , check the magneto, points and condenser............

it is all cheap enough, just takes time, and sweat to bring her back...........

decarb info is here: http://forums.iboats.com/showthread.php?t=299680

let us know how it going, please????

 

[hidef]

Re: 1973 4 horse johnson

Use 24:1 for your fuel mix 50:1 isn't rich enough as that engine still uses bushings. Clean the carb if parts from the old fuel pump or rubber from the old fuel lines made it into the carb you could have plugged passages.

 

[hobojoe]

Re: 1973 4 horse johnson

i dont know anything about a thermastat.but good to know that it just spits a little water.he bought motor last year,first time out this year started on first pull,prob went 1/2 mile and stopped we fished all night and would only run for a min or 2 at a time. when priming ball would not re inflate.so used trolly and oar to get back to launch.took hose off fuel pump and had rubber in it so disected the ball and the interior had decintergrated (dont know why) so got a new feul pump(which looks a little bigger then the one that came off)tank,hose and ball. my brother is a little impatiant and tries to start and plays with the knobs and being leagaly blind when i go over ask what he turned he cant tell me. raining today so wont be able to go over and try turning in slow speed. i did turn in and i think where it seems to want to try and start is like 2 1/2 turns or so. but when it does run it sounds great. if not a little fast. it sound more powerfull then before changing the pump and hose. i am a poor typest so thanks everyone and will keep you informed joe

 

[tx1961whaler]

Re: 1973 4 horse johnson

If the primer bulb and fuel line came apart, then you can bet that the carb is clogged up with little bits of rubber.

 

[hidef]

Re: 1973 4 horse johnson

The four horse doesn't have a thermostat so no issue there. They do spit water out of the relief ports and spit is the proper term because you won't see a steady stream. You carb is most likely plugged with rubber bits. The old hoses are not ethanol resistant so running new fuel in the engine caused the old fuel lines to breakdown and fall a part.

 

[hobojoe]

Re: 1973 4 horse johnson

ok went over today,started on third or fourth pull but had to have slow speed dial set at 4.5 turns.then shut it off went to restart and starter cord broke.figures. got new cord then spring came out spent2 hours trying to get that back together..then managed to get started at 2.5 turns on warm start. but motor still seams to speed up and slow down on its own. running it in a barrel. bro said he might see how much to get it tuned up or carb cleaned.but also said we might go to the lake tommarow night.keeping fingers crossed last time out had 15mph winds and motor ran long enough to get away from shore and he didnt bring trolling mtr so had to row and sit on shore all night (we get dropped off) till ride came at 6 in the morn.and all caught was 2 cats.

 

[lindy46]

Re: 1973 4 horse johnson

Carb needs cleaning/rebuild. The idle circuit sounds like it's gunked up which causes the change in speed.

 

[hobojoe]

Re: 1973 4 horse johnson

wound up taking it to a mech,charged $40 to clean carb .they said was pretty gunked up. took it home starts on 3rd pull cold and 1 or 2 when warm.asked about the 24:1 oil mix they said they wouldnt,maybe a heavy 50:1. this is a good place and friendly place to find help.thanks all joe and mike

 

[nwcove]

Re: 1973 4 horse johnson

i really wouldnt go any lighter than 32:1 on the mix, and i would also consider an inline filter for the fuel line from the tank. ( $5 part at any hardware store)