72 50hp Johnson hard start

[djserd]

My 1972 50 horse Johnson is hard to start, gets spark, gets fuel, just takes a while to get going. Once it is started it runs good. Wondering what might be the issue here. One thing is that the cold start lever on the control box doesnt seem to work properly. Kind of works when it wants to. All the way up some times will idle high on start up, but very seldom. But when I put it back in neutral after moving away from the dock it idles right up. Once the motor is warm, no problem starting at all. Any info on this would be greatly appreciated

 

[tashasdaddy]

Re: 72 50hp Johnson hard start

you probably have cable problems. streched cable, is your choke working. do you have good strong fully charged battery, they have to turn about 300 rpms to start.

 

[djserd]

Re: 72 50hp Johnson hard start

Funny you should say that. Because after I posted that last night I was looking at cables on IBoats and it looks like the one that is on there now is for " 1979-later". My motor is a 72.... However, things seem to fit right on both ends, It is definetly the right cable for the control, maybe not the motor. But there is only a prob with cold start, not the actual throttl...I'll keep trying to figure it out.

 

[djserd]

Re: 72 50hp Johnson hard start

And yes, the choke seems to be working fine, I use the manual option instead the automatic. Would a battery with higher CCA's turn the motor faster?

 

[Silvertip]

Re: 72 50hp Johnson hard start

Higher cranking amps only makes a difference if the current battery is smaller than recommended. A starter motor "draws" current from a battery. If the battery can't supply that capacity, yes a higher capacity battery is needed. But if the battery is the correct size, adding one with still more capacity does nothing except extend the amount of time it will crank the engine. If you have a 300 - 350 CCA battery now, and provided it is fully charged and actually a "good" battery it should be fine. If you can use the fast idle lever with the engine in gear, then something is wrong with the control box. There is an interlock that should prevent that lever from being raised when the engine is in forward or reverse.

 

[djserd]

Re: 72 50hp Johnson hard start

Battery is brand new, though I did buy a small one that was for "marine starting" at NAPA. I have used one of the batteries out of my 94 F-250 Turbo diesel (my fourth child), it seemed to crank it faster, but I wasn't sure if it was because the other one was getting weak from trying to start or not.
As far as the Control box, I have had it apart twice, and it will only go togather one way, its actualy harder to push that lever all the way down when it is in gear.

 

[Lodgepole]

Re: 72 50hp Johnson hard start

My control box had a problem with the fast idle lever. There is a roller that goes on the pin inside the slot in the lever. Mine was dissentigrated and was gone. I was told they are not available so I made a roller and put a little grease on it. No more troubles. Also a good thermostat sure makes the 3 cy. a lot more user friendly.

 

[djserd]

Re: 72 50hp Johnson hard start

Took it out this morning for some N.W trout fishing and found the the choke was not closing all the way...huge difference in starting time. I'm not going to mess with it however. I does start and runs good, I don't plan on having it more than through next summer, so I'll just leave it be.