'75 Johnson 4hp Need some HELP PLEASE!!!

WATERTIMES

Seaman
Joined
Jun 13, 2008
Messages
67
Okay,
I just got back from Cape Cod , and went and put on a new head gasket as well as a carb rebuild kit. Still no solution to my "NO RPM's" in fast speed.She starts 3rd pull and runs all day long til I shut her down. I'm hoping someone can point me in the right direction as to what I should be lookin at. I thought that maybe the points slipped out of adjustment because after doing the tune up, it did hit high rpm's then it decided not to do it anymore.Should I be thinkin it's the points? I have the carb float set at 1-1/8" , should I have it set further? It does at times want to clear up and run at high rpm's but just doesn't get there. Any suggestions?
 

g26rebel

Cadet
Joined
Jul 12, 2008
Messages
8
Re: '75 Johnson 4hp Need some HELP PLEASE!!!

could it be that the timing doesnt advance with the throttle being advanced?

are you in Mass? i own a small repair shop and would be glad to take a look at it for you!
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: '75 Johnson 4hp Need some HELP PLEASE!!!

i think i would try this before anything else. i used it on my motor, and have never touched it again.


(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle va /lve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

WATERTIMES

Seaman
Joined
Jun 13, 2008
Messages
67
Re: '75 Johnson 4hp Need some HELP PLEASE!!!

tashasdaddy, I was out there for about 3hrs.,tryin to find that sweet spot,
with no avail,I would get close but there still was no rpm's to be found,I shut her down last night at 10:30pm with a pretty good setting but w/o high rpm's.

g26rebel, we go once a year to the Cape,I live near Albany NY. The timing thing makes me wonder. When I first initially start her and I give it a quick full speed she does wanna clear up but then she sticks with the troll speed.

Does this sound like a timing issue,before I go takin the fly wheel off, awl hell,
I'll probably do that anyway,I guess I'll see what the points are set at, just to
cure my curiosity. Any other things I should be lookin at?
 

WATERTIMES

Seaman
Joined
Jun 13, 2008
Messages
67
Re: '75 Johnson 4hp Need some HELP PLEASE!!!

Oh, I wanted to run this by somebody,when I took off the flywheel the
very first time to replace the package there was a felt strip ridin along the crankshaft but was connected to the points assembly,it was as worn as worn can get,so I took that off and replaced it with the one that came with my new set, was I supposed to do that or was that just to lube the parts then discard? This CLYMER manual doesn't get too specific or into much detail depth.
 
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