I'm beginning to despair of ever getting my Malta O/B to run properly

many years ago a mate had a generator started purfectly ran for 15 sec , cut out, wouldnt start for2 mins, then easily start again and do the same again.

The clue was when stopped, petrol vapor as a mist came out from the carb.

Cause , a blocked exhaust anti spark gauze.

Is the exhaust side not blocked or partially bunged up with carbon or other blockage / salts etc
 
david_bagshaw said:
many years ago a mate had a generator started purfectly ran for 15 sec , cut out, wouldnt start for2 mins, then easily start again and do the same again.

The clue was when stopped, petrol vapor as a mist came out from the carb.

Cause , a blocked exhaust anti spark gauze.

Is the exhaust side not blocked or partially bunged up with carbon or other blockage / salts etc
Click to expand...
Another reason for dismantling the whole thing.
 
Yellow Ballad said:
For what they cost and the time it would take stick some new crank seals in but even if they were worn, once the engine is started you can normally tickle the throttle to keep the engine going as there's enough crankcase pressure in a running engine. It would however normally pop and puff with little power and struggle to start.
Click to expand...

It could be that it turns out to be necessary, but the time and cost ain't going to be trivial when you factor in the snapped bolts, helicoiling and ordering new. Having said that, it's a good idea to do it now when there's plenty of time on hand because you also get to clean out the waterways - virtually solid on my spare.
 
david_bagshaw said:
many years ago a mate had a generator started purfectly ran for 15 sec , cut out, wouldnt start for2 mins, then easily start again and do the same again.

The clue was when stopped, petrol vapor as a mist came out from the carb.
Cause , a blocked exhaust anti spark gauze.
Is the exhaust side not blocked or partially bunged up with carbon or other blockage / salts etc
Click to expand...
davidej said:
Another reason for dismantling the whole thing.
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I dont understand what part of the exhaust system David Bagshaw thinks could be blocked . There is no anti spark guard as far as I can see.

However if you are running it in a barrel with the lower unit submerged, as i hope you are, it might be worth checking the back-pressure relief port which under a small cover on the back of the leg below the lower swivel. Normally some exhaust gas will blow out from here together with a little water as droplets or a mist

Have you checked the float height as i suggested

Have you checked that you have a good hot blue spark which will easily jump over 1/4" ?

I find it difficult to believe that it would start easily if the crankcase seals are bad
 
If it' s the spark crapping out, the plug will be wet after it's died.

The ignition is likely to be quite reliable and the magneto has more oomph at running rpm than with a mere human pulling the starter cord.
That said, nothing should be beyond suspicion.
Blocked exhaust, seen that on 2T bikes which potter through traffic a lot, in the days of premix fuel.
It seems unlikely that an outboard exhaust will block. But when you are really convinced you've run out of 'likely' causes, you have to look at the others.

There comes a point when you risk reducing a saleable 'not quite runner' to a pile of bits.
 
davidej said:
Yes to the float height.

As to spark. i tested with an old plug and I could get it to jump about 3mm but not 1/4" ie 6mm
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If I can see the spark in daylight (not bright sun of course) - then for me that's good. Given the older magneto stuff of years gone by ... many you couldn't see the spark without shielding from light !!
 
davidej said:
Yes to the float height.

As to spark. i tested with an old plug and I could get it to jump about 3mm but not 1/4" ie 6mm
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That's not good enough although I dont understand what you are doing with an old plug

If you don't have an adjustable spark tester improvise something
( Lakesailor made a tester with a couple of nails through a piece of dry wood, points bent over towards each other, HT lead to one, the other earthed)

I said 1/4" but was being cautious. (I'd really expect to be able to get a spark to jump 7/16" with a CD ignition, 5/16" with a points system)

No point in proceeding, esp tearing the whole thing apart, until you are satisfied that the spark is up to scratch .
 
Refueler said:
If I can see the spark in daylight (not bright sun of course) - then for me that's good. Given the older magneto stuff of years gone by ... many you couldn't see the spark without shielding from light !!
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The spark on the malta isn't very bright or even powerful, well that's the situation on both of mine. I still feel that it is a carb problem and linked mainly to the slow running jet which caused no end of problems on mine. I've never noticed any way of adjusting the float height and when I have put a new float in it just worked.
 
Boathook said:
The spark on the malta isn't very bright or even powerful, well that's the situation on both of mine. I still feel that it is a carb problem and linked mainly to the slow running jet which caused no end of problems on mine. I've never noticed any way of adjusting the float height and when I have put a new float in it just worked.
Click to expand...

I'm with you mate ... an engine does not speed up on its own due to spark / ignition electrics problem !

Speeding up seconds after starting is classic fuel starvation.
 
Refueler said:
I'm with you mate ... an engine does not speed up on its own due to spark / ignition electrics problem !

Speeding up seconds after starting is classic fuel starvation.
Click to expand...
I also agree with you ..... but I'm very surprised that the engine does not fire when a little fuel is sprayed directly into the air intake which cranking her over. I've never know this to fail if the electrics are OK. :unsure:

Richard
 
RichardS said:
I also agree with you ..... but I'm very surprised that the engine does not fire when a little fuel is sprayed directly into the air intake which cranking her over. I've never know this to fail if the electrics are OK. :unsure:

Richard
Click to expand...
Quite... which is why I asked about the spark again
 
RichardS said:
I also agree with you ..... but I'm very surprised that the engine does not fire when a little fuel is sprayed directly into the air intake which cranking her over. I've never know this to fail if the electrics are OK. :unsure:

Richard
Click to expand...

I have a few thoughts about this ...... but without standing by the side of OP to watch how he sprays etc - I cannot say ....
 
VicS said:
Quite... which is why I asked about the spark again
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I have to comment that if any of my outboards could generate a 7/16" spark .... I'd be wondering how it was doing it ...

I have CDI on many engines I use from 15cc up to the larger B&S Generators etc. ...... they all give very good sparks ... but 7/16" ?? That's near 12mm ..... that's one hell of a gap ...

What are you using ? Van de Graf generator ?
 
Refueler said:
I have to comment that if any of my outboards could generate a 7/16" spark .... I'd be wondering how it was doing it ...

I have CDI on many engines I use from 15cc up to the larger B&S Generators etc. ...... they all give very good sparks ... but 7/16" ?? That's near 12mm ..... that's one hell of a gap ...

What are you using ? Van de Graf generator ?
Click to expand...
Indeed.
Many ignition systems have a 'safety gap' in them to limit the spark volts. Others can be damaged by too big a gap.
 
Paulg25 said:
Best way I've found of checking ignition systems is to use a can of easy start.
Click to expand...

Easy start contrary to some thinking - is actually for Gasoline and Diesel Engines ...

I had to use it other day on my Mariner 20 2str - which fuel had settled and I didn't shake tank enough !! So a dose of oil went in carb ... few starts on ES soon had her up and running ....

I wouldn't normally use it ... prefer gasoline spray ... but when needs need ...
 
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