1979 4hp Johnson Sea Horse running issues

[jhightower31]

I just rebuilt the carb and replaced the water pump. I do not know how the motor ran before this because the carb needed to be rebuilt. It is very hard (pita, not hard to turnover) to start. I have to sit there and keep adjusting the slow/fast knob until I find the sweet spot that it will finally start. It also seems that the choke is very temperamental. Once it is warmed up I can barely push the choke in because it wants to die. It will run in the fast speed but will not stay running in slow speed.

The float was checked to make sure it was in spec when it was replaced and yet it still leaks fuel out of the throat of the carb while trying to start it. Is this normal? One of the plugs look like it is firing right, has a slight brown to it but the other plug is all black. It doesn't look like carbon build up though.

I did just clean the plug up and both plugs do have spark. After getting it to run and letting it run about 10 minutes the power head is very hot, it is to the point that it is heating up the fuel tank mounting bracket at the rear so bad that you can't even touch it. I do not have a temp stick to see if it is over heating or not.

 

[ondarvr]

Re: 1979 4hp Johnson Sea Horse running issues

The carb needs to be cleaned and the float needle replaced and then replace the water pump impeller and thermostat. After that you can start fine tuning it.

I know you said you cleaned it, but in reality even experienced people need to do it again sometimes because there can be hidden gunk you didn't get the first time around.

 

[Daviet]

Re: 1979 4hp Johnson Sea Horse running issues

Start at the beginning, what is the compression like? What about the spark, will it jump a 7/16" gap and is it bright blue?
I know you said you replaced the impeller but what does the pump housing look like, is it all pitted up? Some of those small engines did not have a thermostat, but a bad head gasket could allow compression into the cooling system and cause it to overheat.
When you overhauled the carb, did you remove the core plug on top of the carb and clean all the passages inside? It does sound like there is something holding the needle off of the seat allowing fuel to leak by, might need to open it back up and check.
Just some things to think about.

 

[jhightower31]

Re: 1979 4hp Johnson Sea Horse running issues

Haven't checked the compression on it, wasn't able to until I got the motor running but haven't done it yet. Haven't tried to set it at 7/16 to watch the spark. Are you talking about setting the gap that large or setting it away from the housing at that distance to see if it sparks?

The water pump was a complete rebuild kit, housing, impeller, wear disc, screws, o-ring for top of drive shaft. The core plug was not removed from the carb because the guy that rebuilt it said he saw no need to remove it because the carb looked to be in good shape as it was. The float was replaced, the float valve seat, and the small cork o-rings/washers what ever you call them.

Here is a link for the gearcase following numbers were in the rebuild kit for the water pump. 12, 13, 14, 15, 16, 17, 18, 19 & 27
http://www.crowleymarine.com/johnson-evinrude/parts/31506.cfm

Here is a link of the carb, the following numbers were replaced. 11, 12, 13, 14, 22, 8, 34, & 15. Not sure if there was anything else because I do not have my parts catalog here with me right now to verify what exactly included in the rebuild kit. Number 5 was not pulled out.
http://www.crowleymarine.com/johnson-evinrude/parts/31501.cfm

This motor does not have a thermostat, it is a 4hp 1979 Sea-Horse. They don't even have a neutral or reverse gear. Require you to spin the whole motor around to have reverse.

 

[Rick.]

Re: 1979 4hp Johnson Sea Horse running issues

"Haven't checked the compression on it, wasn't able to until I got the motor running but haven't done it yet. Haven't tried to set it at 7/16 to watch the spark. Are you talking about setting the gap that large or setting it away from the housing at that distance to see if it sparks?"

You do not need to have it running in order to check the compression. To test the spark to see if it will jump 7/16 you need to purchase an adjustable spark tester for about 10 dollars. With it you can simply adjust the gap to any reasonable distance. Your spark needs to blue/white and snappy.

"The water pump was a complete rebuild kit, housing, impeller, wear disc, screws, o-ring for top of drive shaft. The core plug was not removed from the carb because the guy that rebuilt it said he saw no need to remove it because the carb looked to be in good shape as it was. The float was replaced, the float valve seat, and the small cork o-rings/washers what ever you call them.


Here is a link for the gearcase following numbers were in the rebuild kit for the water pump. 12, 13, 14, 15, 16, 17, 18, 19 & 27
http://www.crowleymarine.com/johnson...arts/31506.cfm

Here is a link of the carb, the following numbers were replaced. 11, 12, 13, 14, 22, 8, 34, & 15. Not sure if there was anything else because I do not have my parts catalog here with me right now to verify what exactly included in the rebuild kit. Number 5 was not pulled out.
http://www.crowleymarine.com/johnson...arts/31501.cfm"

Have a look at this link for your parts diagram. It is always available and you can keep increasing the size until even I can read all the numbers.

http://epc.brp.com/Index.aspx?lang=E&s1=bc35cbad-2980-49a1-9219-3458628f5406

I would suggest you have a look at the Top Secret File at the top of this forum. There is lots and lots of really good information that you might find useful. Not specific to your 4HP but good general information that you can apply to your 4HP.

http://forums.iboats.com/showthread.php?t=299680

Let us know how your making out. I think you have a real gem there which will last a very long time once you get the bugs out of it. I have a 71 - 4HP Evinrude which I have recently started using as a kicker. Best of luck. Rick.