Johnson 25HP 1970 cold start question

[Mandelain]

I have bought a Johnson 25 HP engine from 1970.

I have read the forum FAQ and other related posts but did not find the answer.

I cant get my engine to start the normal way.
What do I do?
- Pump the gastank after opening the air.
- Pul the Choke
- give it a firm pull

When puch the choke back and pull it. Then sometimes its fires a couple of times and then stalls. With the choke out it does nothing.

Here's the strange thing
When I put the engine in gear and i open the throttle than put it back in nutral It will start but then the engine overrefs. When I put the throttle back it stalls again. So when i want to take a spin i have to put it in gear directly and leave it there. When it runs it runs good. The idle speed is a bit to high.

What must I do or adjust to get it tu run in nutral ?

I am from the Netherlands so please excuse my writing. I hope someone can help

 

[lindy46]

Re: Johnson 25HP 1970 cold start question

Sounds like you need to clean/rebuild the carb.

 

[Mandelain]

Re: Johnson 25HP 1970 cold start question

Thanks for the fast reply

I will do so but I wonder what causes this behavour.

 

[Haffiman]

Re: Johnson 25HP 1970 cold start question

To get an engine running, you need correct temp (water pump and thermostat?), you need a working ignition system (spark test?), you need a correct air-fuel mixture (clean/rebuild carb?)
If you have the above correct, your engine will be working.
Dried up fuel mix may clog carb jets, the fuel of today eats away the rubber of yesterday (gaskets, hoses).

 

[Mandelain]

Re: Johnson 25HP 1970 cold start question

I opened the engine up but need to find a way to remove the carbs the right way (dont want to break something)

As I have a nice spark It has to be fuel

Will get back and post my findings

Thanks

 

[Mandelain]

Re: Johnson 25HP 1970 cold start question

Didnt remove the carbs. I saw that the slowspeed knob was disconnected. (linkadge gone) So I started by removing the slowspeed needle from the carb and cleaned it. That didnt do anything. What did the trick was to turn the needle clochwise and after a couple of twistrs It began to stutter and now it purs like a 2stroke kitten (maybe lion is a better compairisson)

Thanks for pushing me in the right direction.

 

[kfa4303]

Re: Johnson 25HP 1970 cold start question

This may help for future reference too:


http://forums.iboats.com/showthread.php?t=167352