Hi all. Ok, I realise straightaway that it's not the done thing to reply to an old post, particularly one that's over ten years of age! However, I do have a good reason. I've now bought the boat from 'Giles' (Nidri240) that he bought in 2005. And yes, it comes complete with a Mariner 6hp of 1999 vintage. And guess what, it STILL doesn't start. Well, it does now start but not in the correct way Mariner intended. After a whole evening trawling the net to try to find an answer, I've stumbled across this thread that Giles began all those years ago.
I'm using fresh fuel, new plugs and have performed another full carb stripdown. I also removed the Reed valve plate and found the petals covered in an orange coloured gunge which I carefully cleaned off, before re-assembly. The primer bulb on the tank is good, the filter is clean and a good flow of fuel goes in to the carb. The float works and the needle is clean and new looking. The jets are also clean. The fuel pump diaphragm is good, and the gaskets between the carb and reed block and reed block to powerhead are also perfect.
The only thing that doesn't seem to be doing anything is the blue primer button. Again, I've had it all apart, and it looks like new inside with no blockages. However, when the blue button is depressed manually, or by pulling out the choke button, I am expecting to see a shot of fuel go into the carb venturi. I don't see anything at all. Does the fuel squirt in behind the butterfly?
This thing is a pig to start whether using the choke/increased slow running/altered timing knob or not. But, if I hold a tissue over the venturi, it starts instantly, suggesting to me that the choke mechanism isn't working. As soon as it's running it will purr all day if I want it to. Let it go cold though and it's no go until I again manually choke it with said tissue.
This is clearly at least a ten year old problem, and I'm determined to fix it. Does anyone have any idea's what's going wrong?
