Johnson 6hp 1974, starting problems

[german]

hi,
i have a johnson sea-horse 6hp 1974.
the outboard runs well, but it takes like 10 pulls to make it start, and sometimes when in gear at low rpm's stops running.
what could be the problem?
thanks
german

 

[Vic.S]

Re: Johnson 6hp 1974, starting problems

A number of things to check

Plugs: Correct type, clean, good condition (no cracks) and correctly gapped. Any doubts replace with new.

Plug leads in good condition.

Points (breaker): (This is a coil and points ignition system) in good condition and correctly gapped and spring not lost all of its tension. Replace if any doubts.

Coil: Inspect for any obvious deterioration of insulation. A common problem it seems

A failing condenser will make it progressively more difficult to start. Replacing is the only realistic way to check.

Overall check of the ignition system is a good heathy spark if a plug is removed and held against the engine while cranking

Fuel: Reasonably fresh. Will keep if stored properly but if old best to replace.

Choke closing properly?

Mixture setting correct?

Carb flooding slightly due to poorly seating valve? (unlikely but possible)

Carb needs cleaning especially if you have to screw out the idle mixture adjustment much beyond the normal 1.5 turns. (Spraying a carb cleaner through will achieve nothing. if it needs cleaning then the jets need to be removed and physically cleaned after a soak in carb cleaner but not with anything which will damage them.

Stopping at low speeds could be due to the idle speed being set too low but several of the above could also cause it especially the fuel/carb items.

Check out the FAQs. first item on the main forum index

 

[german]

Re: Johnson 6hp 1974, starting problems

hi Vic,

thanks for you suggestions.
what abou the fuel pump? do you think that could be a problem?
and compression? will low compression make the engine difficult to start, but will show no problems while running?
is there any way to check compression without a compression meter? To buy one is half the price of the engine.

thanks
german

 

[wbeaton]

Re: Johnson 6hp 1974, starting problems

My compression tester cost $15 at Princess Auto. It works great.

 

[steelespike]

Re: Johnson 6hp 1974, starting problems

Before doing all those great suggestions Check and clean the the plugs Should be champion J4C set at .030.Check for spark.It should be nice blue and you should here it snap.
You can get an idea of the compression by putting your thumb over the plug hole and cranking.Should be pretty hard to contain the compression.If the motor has sat around a lot the fuel system probably needs checking and repair with special attention to cleaning.
If the primer bulb gets hard wehen you prime to start the pump is not likely to cause hard starting.With a bad pump it isn't likely to run well.
If it seems really smokey and kind of shudders when it first starts it may be flooding.

 

[Paul Moir]

Re: Johnson 6hp 1974, starting problems

The fuel pump wouldn't have anything to do with a starting problem since the outboard primed with the primer. Pumping the primer while running will show various problems though:
Pumping makes the engine run worse - leaking needle & seat in the carb. Hole in fuel pump diaphram.
Pumping makes the engine rune better - Leaking fuel line fittings, fuel line restrictions, weak fuel pump, tank venting problem.
Pumping makes no difference - fuel delivery system is working normally.

Poor compression will make an engine difficult to start without showing distinct problems while running. It will be less powerful and can idle worse, but power is hard to verify without comparison, and the idle trouble can be masked by setting the idle high.

How long does it run before it conks out? Will it restart right away again? Does it always take 10 pulls, even warmed up?

You can determine if it's a fuel problem or an ignition problem by spraying a little 50:1 mix down the carb's throat with a windex type bottle and trying to start on that.

Veryify though that the choke completely closes. Try adjusting your idle mix a little richer (counter clock wise) as that will make a big difference starting.

EDIT: Slow behind steelspike there. Plugs should be J6C gapped at .030" according to all my sources though.

 

[steelespike]

Re: Johnson 6hp 1974, starting problems

I some how thought we were dealing with an older motor Nice catch Paul.
Incidently I have 2 1970 manuals,one says J4C the other gives you a choice. My 89 manual says simply J4C for 69-70.Obviously this has no bearing on a 74.

 

[Paul Moir]

Re: Johnson 6hp 1974, starting problems

My sources can also be wrong. The most convincing I have is the spark plug chart from the (OEM) J/E Service Parts catalogue which says J6C for all 6hp engines '65-'76.

Just checking the BRP parts site, they have the old J6J listed as the spark plug for that engine, but the J4J listed for the '70. I wonder what made them change? Both have thermostats (the old rule of thumb for J6J vs J4J), etc.

 

[Vic.S]

Re: Johnson 6hp 1974, starting problems

Just a comment about compression.

If you beg borrow or steal a tester expect to get no more than 90 psi on this (or any 2 stroke ) engine.

 

[tashasdaddy]

Re: Johnson 6hp 1974, starting problems

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035554

 

[freddyray21]

Re: Johnson 6hp 1974, starting problems

90 lbs is okay but I disagree that you will only get 90lbs on any two stroke I have had several with lots more compression than that