Outboard trouble

[firstascent2002]

Hi guys,

I've got a mariner 3.3 outboard. It has bever been really well behaved but has recently developed a new problem. It starts fine and in a wheeley bin at home will idle and run at low speeds fine. Down at the boat it's a different story. Starts fine and runs at lowish revs ok but dies if the revs are increased. Keeping the choke half open puts off the eventual stall for 10 or 15 minutes sometimes but it always comes. It has had new fuel and a new spark plug this year and I put a can of quicksilver carb cleaner through it. It did get dropped in to the drink about a month into its ownership in 2001. It was out in the blink of an eye and went to a rescue man who had it running sweat as a nut afterwards but it has always had a tendency to be tricky and I wonder if I'm better selling it for spares / repair and starting again...I may even go electric...how my wife would love that. j

 

[gandy]

Sounds like fuel starvation to me.

Or we had similar symptoms from water in the fuel - it would start and run OK, but die if you opened the throttle. When I drained the carb quite a bit of water could be seen in the fuel.

 

[Lakesailor]

I'd go for that. Water in the fuel is a constant battle, I find.

A partially blocked main jet also would fit the bill. Nothing beats dismantling and blowing through with an air line. Carb cleaner doesn't always do it.

(..........waits for HSE warnings)

 

[gandy]

[ QUOTE ]
(..........waits for HSE warnings)

[/ QUOTE ]
HSE Warning - don't stick the air line up your backside.

 

[charles_reed]

Water in fuel system

You really need to strip it down and thoroughly clean out the tank.

The Mariner 3.3, Mercury 3.3 and Tohatsu 3.5 are all the same engine, extremely reliable and very good starters.

Tohatsu spares tend to be more reasonably priced.

 

[simonfraser]

Re: Water in fuel system

you got a blocked fuel jet, clean them out, sorted mine no prob
there could be one jet for idling, one for slow and one for fast etc.

 

[Kawasaki]

When you "Ask" the eng for more go, it goes onto main jet.
There are only 2 jets.
Pilot (up to about quarter throttle ish) then the main comes in.
The main will be affected if their is water in the float bowl.
You say it starts and runs ok.
Fiddling with the choke suggests a main jet prob.
If you had a leccy prob it wouldn't start and idle properly unless the HT side was about to pack in.
Then it would probably pack in totally after a bit.
It will run a bit differently in the bin.
As said, make sure there is no water in the tank.
Stick another plug in anyway.
Strip and clean the carb again and again if ness.
Can't see it's brief swim a few years back will have affected the symptom the motor has.
If the crank seals were not up to scratch (after the dunking) idling would be affected.The motor is quite simple really.
Does it sound ok when idling?
IE any rattles or missing and spluttering and will She idle reliably for a minute or two.
I ask for a reason.

 

[mandlmaunder]

Re: Water in fuel system

All above is likely true (apart from HSE warning, you can do that with an air hose but must have decomp chamber or large pin near by,but why would you?).
Also check airfilter and air galleries.

 

[gandy]

On our Merc 2.2 carb I couldn't find any form of pilot jet, I looked for one when having problems with ours. The manual suggests the 3.3 is the same. Just one jet and needle.

 

[boguing]

I'm with LS on this. Water - particularly in the float bowl. You'll find a drain screw under it. Catch a sample in a transparent container, £ to a penny you'll see two liquids. If so, drain the tank, filter and start again.

 

[firstascent2002]

Thanks for the thoughts. That carb is a comming off. I don't have a high pressure air line, will the compressed air cylinders from maplins for cleaning computer parts work I wonder...or maybe I can rig something up from my scuba tank...

 

[boguing]

You don't need compressed air - in fact, don't use it, you could crush the float.

For a good sort out, just unscrew the float bowl (four or five screws on the bottom of the carb), remove the float and the screws that you can see within and blow through them and the holes that they came from. Similarly, with the float off (usually a pin that you can easily push out), the main jet plunger will fall out. Blow that one through too. Clean the bowl out with a brush - those brown bits - and re-assemble. Change the fuel by draining the tank upside-down. Change the fuel filter. While it's off, blow the lines through (all by mouth). If you can identify the fuel 'pump' (twixt tank and filter or filter and carb, remove it and do likewise. (Silly not to once you have the screwdriver out).

give the float a shake by your ear - if it's got liquid in it it's dead and needs to be replaced.

Nothing else does, the gasket, as long as you didn't tear it on removing the bowl, will be fine for a few more exploratories.

Hey Presto - new engine. For a while.

 

[Kawasaki]

Your correct.
There actually is no pilot "Jet".
There is an orrofice (small hole) which dictates the fuel given before the main jet"Sucks"
That is a decent diagramn which explains the bits properly.
10 throttle slide
26 choke blade/ slide
22 tickover screw
17 fuel needle valve
11 main jet
23 tickover screw spring
29 fuel needle vave.
Too late to discuss furhter
Need a Dram!
Goodnight
R k