I'm tearing my hair out over my outboard!

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davidej

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It is a Yamaha Malta 2-stroke, oldish but not a lot of use and normally very reliable.

At the end of last season, I emptied out the fuel and ran the float chamber dry in a fresh-water tank to keep the waterways clean.

This season, fresh petrol and it started easily and ran well but won't tick-over. I have taken the carb off, made sure the float chamber was clean (it was) and blew through all the passages with carb cleaner. It all looked as good as the day it was made.

Yesterday I used it to go out to my moorings and it runs at full or half throttle like a good un. However as I go below about a quarter throttle it dies on me. This means I have to start in gear at too high a throttle setting so when it fires it races off. Not very satisfactory.

I have just cleaned the carb again this morning in case I missed something. Put it in the tank and still the same result. I thought I knew about 2-strokes but this is really stumping me.
 
I may be telling you something you already know but your slow running jet is partially/completely blocked.

The bad news is that it may not be fuel residue but ali corrosion.

I have seen this befoe on engines that have been stored for a while.

Try blowing through then as a last resort poking with fine wire.

If that fails it is a new carb.
 
I had a similar problem with mine, one of a few things which i honestly thought was the problem but, first was a blockage in the cap air screw which slowly caused it to cut out at low speeds, plug was a brand new one which was faulty which i feel was the cause but not totally sure, the tap had a fault which when the pipe was removed fuel flowed slowly which when blown out with high pressure air it increased, altered the oil mix aswell.
So really not sure what i did to cure it lol.
 
davidej said:
It is a Yamaha Malta 2-stroke, oldish but not a lot of use and normally very reliable.


I have just cleaned the carb again this morning in case I missed something. Put it in the tank and still the same result. I thought I knew about 2-strokes but this is really stumping me.
Click to expand...

The symptoms are those of a blocked or partly blocked slow running jet, especially if playing with the choke will help.
Clean as suggested by poking through with a soft copper wire.
Perhaps flooding due to float valve not seating.??????

BUT

Despite the the obvious check the spark. You should be able to get a good strong spark capable of jumping several mm

If you have not done so change the spark plug ..... so often that solves a problem which logic says is fuel/carb related
 
I had this problem this spring as well with my Malta. I stripped the carb down as much as possible and removed the slow running jet and the put the whole carb in a pan of cold water and boiled it for 15 minutes. Problem solved. It used to be an old timers trick with all 2 stroke engines and multi jet carbs. Unfortunately l now find that I'm now an old timer. I don't really recommend poking bits of wire in holes. The holes are precission made and scrapings can get stuck and/or you wedge the blockage in tight.
Remember to carefully note the position of the slow running jet and count the number of turns it takes to remove it. You will need to finely tune it once it's running again. It might take a couple of boilings for stubborn blocks but it will clear it.
It also works on lawn mowers, strimmers, chain saws etc., etc.
Mike
 
In fact, have you put the slow running adjuster (pilot jet screw) back in the right position.
For the Malta it seems to be that you screw it down to the fully closed position and then back it off 1 + 1/4 turns. People generally say 1 + 1/2 turns if there isn't any thing to suggest otherwise.
 
{If you have not done so change the spark plug ..... so often that solves a problem which logic says is fuel/carb related}
It's just cost me near £40 to find that out :(
I had cleaned and checked everything except replacing plug ( 'cus I didn't have one) to solve a cutting out at higher revs problem!
 
As well what has been said I have also found if the float level is set to low (most are adjustable by bending the bracket) At tickover the engine does not seem to produce enough vacuum to raise the petrol high enough to mix with the incoming air.
 
davidej said:
It is a Yamaha Malta 2-stroke, oldish but not a lot of use and normally very reliable.

At the end of last season, I emptied out the fuel and ran the float chamber dry in a fresh-water tank to keep the waterways clean.

This season, fresh petrol and it started easily and ran well but won't tick-over. I have taken the carb off, made sure the float chamber was clean (it was) and blew through all the passages with carb cleaner. It all looked as good as the day it was made.

Yesterday I used it to go out to my moorings and it runs at full or half throttle like a good un. However as I go below about a quarter throttle it dies on me. This means I have to start in gear at too high a throttle setting so when it fires it races off. Not very satisfactory.

I have just cleaned the carb again this morning in case I missed something. Put it in the tank and still the same result. I thought I knew about 2-strokes but this is really stumping me.
Click to expand...
If it really isn't the carb, then I would suspect either a lack of compression (rings, bore?), failing crank seals, or a faulty reed valve if it's that flavour of two stroke?
Or possibly a choked exhaust.
These things usually affect starting as well.
If you can get the carb ultrasonically cleaned though, I'd try that.
 
Vegable said:
I had this problem this spring as well with my Malta. I stripped the carb down as much as possible and removed the slow running jet and the put the whole carb in a pan of cold water and boiled it for 15 minutes. Problem solved. It used to be an old timers trick with all 2 stroke engines and multi jet carbs. Unfortunately l now find that I'm now an old timer. I don't really recommend poking bits of wire in holes. The holes are precission made and scrapings can get stuck and/or you wedge the blockage in tight.
Remember to carefully note the position of the slow running jet and count the number of turns it takes to remove it. You will need to finely tune it once it's running again. It might take a couple of boilings for stubborn blocks but it will clear it.
It also works on lawn mowers, strimmers, chain saws etc., etc.
Mike
Click to expand...
Another trick that sometimes works is to rev it hard then block the intake with the palm of your hand, the increased vacume can suck the blockage through, you may need to clean the plug afterward if you let the engine stop.
 
It certainly sounds like a blocked jet, but I had a similar problem on my Tohatsu 3.5 a couple of years ago and, after stripping & cleaning the carb 4 times, it turned out to be corrosion on the coil earth - a cheap easy fix once we noticed the 'tick-tick-tick' sound of the spark jumping the high resistance. Must be worth checking before spending serious money!
 
Some interestingly different suggestions here.

Having cleaned the carb at least n times (where n is a large number) with compressed air, carb cleaner and fuse wire, I am convinced that is not the problem. I have also changed the plug -all to no effect.

How do I check crankcase seal? I will also look at the electrics
 
Hi there, as previously mentioned get the carb sonic cleaned, you will be surprised how much dirt will come out of it that no amount of poking and blowing with an airline will do, also it will virtually restore the carb to a like new condition and its not an expensive job to have done, leave all the bits in place and get the sonic cleaning shop to strip and put it back together, bet it runs like a dream after :-)
 
Thats a great idea as I have several battery drills where the battery is now dead.

What did you use for the bottom gearbox and to take the thrust of the prop.
 
Rogershaw said:
Thats a great idea as I have several battery drills where the battery is now dead.

What did you use for the bottom gearbox and to take the thrust of the prop.
Click to expand...

Roger, I confess this was just an image I saw today and thought of this thread! But that said, I do believe it a drill chuck with a 90 degree bend.... such as this image.
Could make a trolling rig for some fishin' :cool:

chuck.jpg
 
There is a guy in our marina who has a little dingy powered by a trolling motor but the battery is kept charged with a solar panel

I would like to do the same but trolling motors are very costly here so that pic had given me an idea haw I can do it much cheaper. Thks for the posting
 
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