Suzuki 6hp 2 stroke

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Billows

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I have an ancient one of these bought recently with a boat.It must be as no kill cord.It is a nice light engine so I'd like to keep it.
It starts and runs fine when cold.
When hot it sometimes cuts on low running and is difficult to restart.It runs for a brief period and stops.Leave it for a bit and runs ok again.
It once reved up of its own accord and stopped much to my amazement.
I use 50:1 mixture and proper 2 stroke oil for outboards.It is pumping water through the telltale and exhaust fine too.
What is the diagnosis?
 
Billows said:
I have an ancient one of these bought recently with a boat.It must be as no kill cord.It is a nice light engine so I'd like to keep it.
It starts and runs fine when cold.
When hot it sometimes cuts on low running and is difficult to restart.It runs for a brief period and stops.Leave it for a bit and runs ok again.
It once reved up of its own accord and stopped much to my amazement.
I use 50:1 mixture and proper 2 stroke oil for outboards.It is pumping water through the telltale and exhaust fine too.
What is the diagnosis?
Click to expand...

Hi, It sounds like a fuel supply problem or an airleak.Whenever I run our outboards in the freshwater tank after salt water use I turn the fuel off and let them run dry-so the carb. is empty and wont get blocked with evaporated fuel deposits-they ALWAYS rev up high before they stop. The revs increase as they go lean on the mixture. It will pay to check the tank to carb supply system carefully and hope the crankshaft seals have not dried out. Hope this helps,Good Luck.
 
If you have the handbook on this motor trace the location of the fuel filter.
On my 2.2 it is supposed to be in-line directly beneath /part of the on/off tap, but I've not found it, and it sounds like this may be a partiallly blocked fuel filter.
I also suggest that you undo the drain screw beneath the carburettor, or undo the carb completely and clean out any grunge within, checking the main jet needle and float.(The float sometimes gets stuck when tilting the engine out of the water.
Ensure the plug lead is sound - even try fitting a new plug, it makes a difference.

ianat182
 
I suggest the engine may be running rich which seems ok when cold but when hot the engine will run badlyat low revs and probably stop. If it starts easily without choke this is also a sign. Maybe the choke is stuck partly on.
 
Adjuster is friction control yes.Actually giving it a bit of choke seems to help with the cutting out at low rpm.The fuel bulb is hard when it cuts.There seems to be just one adjustment apart from the throttle stop on the carburetor, something called screw-pilot air.
 
something called screw-pilot air.
Click to expand...
Is the slow running mixture adjustment.

The fact that choking it helps a little suggests that the slow running jet or circuit is restricted.

You could try adjusting the above screw by backing it out a little.
Typically the basic adjustment is to screw it in until it seats gently then to back out 1¼ to 1½ turns then adjusting for best slow running from there.

If you cannot find a setting of the screw that will give good slow running then it pretty well confirms the need for a carb clean.
 
There is also an adjuster screw on the bottom of the carburetor bowl as well as the drain.What could this be for?
 
Is it wise to go messing with these adjustments.I have no experience.Could I do damage?

There is a plastic/rubber tube going from one side of the crankcase to the other labeled a lube tube.There was quite a bit of oil on the crankcase and lower cover when I got the engine, oil seals?

Thanks for all the suggestions by the way.
 
There should be no problem with the adjustment screws.
Don't screw them down hard or you might break the tips off.

Since it runs well at high speed you probably don't need to adjust the one on the bottom but no harm in tweeking the slow running one to see if it makes any difference.

If you strip and clean the carb you will have to remove them and adjust them on re-assembly anyway.

Looking back at the original post before going any further do as rotrax suggested and check the fuel system for air leaks especially at the fuel connector.
If the trouble is due to air leaks though you will be able to keep it going by gently pumping the bulb. You said, however, that the bulb was firm so air in leakage seems unlikely.

If it starts easily I think you can assume that the crankcase seals are OK.


I think you are almost certainly going to have to strip and clean the carb but it is wise to explore other possibilities first.

Have you tried new plugs in it. That's always a sensible first thing to try.
 
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