Mariner 3.3 2 str, N/F model. Starting prob

sarabande

sarabande

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2003 year, with <12 hours running. Has been properly run in, and serviced very carefully.

Petrol mix is exact, and petrol is about 1 month old (premium type)

Symptoms. ( Outboard mounted in wheelie bin; water covers cavitation plate.)

From cold, air tap and fuel tap open, fuel flows to carb bowl in what I consider a decent stream. I have blown back along the fuel pipe into the tank: it's clear. Bowl has been drained and cleaned (just a little waxy stuff at the bottom). Float looks fine, no leaks.

Compression is fine.

Starting prob
Choke to CLOSED, throttle to START mark.

I take up the ratchet and compression on the cord, and heave smartly.

The engine catches for about 2 seconds and a reasonable amount of smoke from the exhaust. Engine dies. An immediate second pull produces no reaction, but leave it for a minute, and the same very short run takes place. Fiddling with choke and throttle does not change the result.

Plug looks OK.

I am not certain of the adjustment screw, but last time I had the engine running, everything was fine and ran nearly full throttle OK.

My manual does not refer to the adjustment of the screw in the carb, but the problem looks to me to be in the fuel flow,


I face East when trying to start the motor, and talk encouragingly about the weather and how we are going to enjoy going on the water.... Any other suggestions please ?
 
granny eggs! But, I've got one of these of a similar vintage and its easy to flood. I generally use about half choke and as soon as it catches dechoke and increase throttle. Also check on/off fuel tap, I had issue there when the clips disintegrated through rust.
 
If you pull the plug out as soon as it stalls and it doesn't look wet or smell strongly of petrol then it's not flooding but probably starvation.

Squirt/pour some 2T mixture (no more than a couple of mls) directly into the carb/air intake and start it again. If it runs for longer before stalling then you have a blocked jet/needle valve (or much too low a float height for some other reason) and stripping and cleaning the carb is the only solution.

You can try squirting fuel into the intake once it starts and you will probably get it to run continuously. This might clear the blockage but it's not always easy to gauge the squirt rate and you might still need a carb strip.

Richard
 
sarabande said:
2003 year, with <12 hours running. Has been properly run in, and serviced very carefully.

Petrol mix is exact, and petrol is about 1 month old (premium type)

Symptoms. ( Outboard mounted in wheelie bin; water covers cavitation plate.)

From cold, air tap and fuel tap open, fuel flows to carb bowl in what I consider a decent stream. I have blown back along the fuel pipe into the tank: it's clear. Bowl has been drained and cleaned (just a little waxy stuff at the bottom). Float looks fine, no leaks.

Compression is fine.

Starting prob
Choke to CLOSED, throttle to START mark.

I take up the ratchet and compression on the cord, and heave smartly.

The engine catches for about 2 seconds and a reasonable amount of smoke from the exhaust. Engine dies. An immediate second pull produces no reaction, but leave it for a minute, and the same very short run takes place. Fiddling with choke and throttle does not change the result.

Plug looks OK.

I am not certain of the adjustment screw, but last time I had the engine running, everything was fine and ran nearly full throttle OK.

My manual does not refer to the adjustment of the screw in the carb, but the problem looks to me to be in the fuel flow,


I face East when trying to start the motor, and talk encouragingly about the weather and how we are going to enjoy going on the water.... Any other suggestions please ?
Click to expand...
If there was waxy stuff in the bowl then the jets are blocked, bite the bullet, easy peasy to do. Pull a wire out of a wire brush to prod the jets.
Stu
 
+1 on Stu's post, but I think that there's only the single jet, as I believe it's a rebadged Tohatsu 3.5, one of which I own, and had an identical problem with. There was waxing/crud in the carb, and I also cleaned the jet with a strand of wire from an electric lead. Cleared immediately, and was very simple.
 
jamie N said:
+1 on Stu's post, but I think that there's only the single jet, as I believe it's a rebadged Tohatsu 3.5, one of which I own, and had an identical problem with. There was waxing/crud in the carb, and I also cleaned the jet with a strand of wire from an electric lead. Cleared immediately, and was very simple.
Click to expand...

Again +1 for the jet clean. This afternoon I have just put together my carb off my own Mariner 3.3hp O/B. You can unscrew the jet quite easily (off the engine of course). The fuel tap was also badly corroded as per another op above and I replaced it accordingly. Change the plug for new cos under load it could fail if old. Check for a decent spark. Could use carb cleaner as well I suppose. First pull sprang to life as if new. Good luck
 
I've double checked the fuel from tank to carb, and the flow rate when the tap is opened is more than enough. The bowl is now shiny alloy and free from gunge as well, so that leaves the jet...

Tomorrow is jet cleaning day :) Oh frabjous joy.


Thanks for help everyone.
 
jimi said:
granny eggs! But, I've got one of these of a similar vintage and its easy to flood. I generally use about half choke and as soon as it catches dechoke and increase throttle. Also check on/off fuel tap, I had issue there when the clips disintegrated through rust.
Click to expand...
I have the tohatsu version of this and agree. Full choke and about 25% throttle until you get any sort of catch, then choke open and go again. Works every time for me
 
sarabande said:
2003 year, with <12 hours running. Has been properly run in, and serviced very carefully.

Petrol mix is exact, and petrol is about 1 month old (premium type)

Symptoms. ( Outboard mounted in wheelie bin; water covers cavitation plate.)

From cold, air tap and fuel tap open, fuel flows to carb bowl in what I consider a decent stream. I have blown back along the fuel pipe into the tank: it's clear. Bowl has been drained and cleaned (just a little waxy stuff at the bottom). Float looks fine, no leaks.

Compression is fine.

Starting prob
Choke to CLOSED, throttle to START mark.

I take up the ratchet and compression on the cord, and heave smartly.

The engine catches for about 2 seconds and a reasonable amount of smoke from the exhaust. Engine dies. An immediate second pull produces no reaction, but leave it for a minute, and the same very short run takes place. Fiddling with choke and throttle does not change the result.

Plug looks OK.

I am not certain of the adjustment screw, but last time I had the engine running, everything was fine and ran nearly full throttle OK.

My manual does not refer to the adjustment of the screw in the carb, but the problem looks to me to be in the fuel flow,


I face East when trying to start the motor, and talk encouragingly about the weather and how we are going to enjoy going on the water.... Any other suggestions please ?
Click to expand...

Premium type petrol?
Bog standard is what to use in a two stroke.
May not be relevant, but-----
 
Bog standard petrol has too much ethanol, and I use premium in chain saws and strimmers. Much better, particularly in keeping the diaphragms and gaskets un-dissolved.

Probably too good for a Seagull, though, which would probably be happy on 50% aftershave and 50% olive oil ?
 
Ludd said:
Premium type petrol?
Bog standard is what to use in a two stroke.
May not be relevant, but-----
Click to expand...

In pre-lead-free days, premium petrol had more lead in it, which could cause 'whiskering' of spark plugs, so makers of two-stroke outboards specifically said to use 'standard' petrol. These days there is no lead in either so nothing wong with premium petrol, possibly even an advantage as it may contain less of the nasty environmentally friendly alcohol muck that absorbs water and I strongly suspect corrodes the alloy carbs of little two-strokes.

40 years ago you used to have to clean/change spark plugs fairly often, but had little trouble with carbs. Now it's the reverse.
 
jwilson said:
In pre-lead-free days, premium petrol had more lead in it, which could cause 'whiskering' of spark plugs, so makers of two-stroke outboards specifically said to use 'standard' petrol. These days there is no lead in either so nothing wong with premium petrol, possibly even an advantage as it may contain less of the nasty environmentally friendly alcohol muck that absorbs water and I strongly suspect corrodes the alloy carbs of little two-strokes.

40 years ago you used to have to clean/change spark plugs fairly often, but had little trouble with carbs. Now it's the reverse.
Click to expand...

My theory is that the 95 has up to 5% alcohol in, good old EU directive? The alcohol absorbs water, the mixture remains in the bowl, the petrol etc evaps leaving some water which reacts with the alloy in the bowl to produce ali salts? Plus it reacts with the brass jets to form copper salts? Carb cleaner was designed to dissolve "varnish" not metal salts. Hence my advice to always use a metal prodder. Despite the text book saying dont prod with metals, all my 60 years fettling has shown that it isnt an issue.
Stu
 
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