Reaching the end of my tether with outboards...non-runner...

[Max...]

Thanks Al, can you elaborate - carbs are a dark art to me. Would that have not been the issue then?

It's the plunger on part D (page 124 below) in the primer system below that was stuck and gunky:

http://boatinfo.no/lib/mercury/manua...0-15.html#/124

If I start with the mixture screw 1.5 turns out is it then a case of moving it to rich then lean and back to get the smoothest idle?

[Max...]

All great now - a bit of a rush last night to pop the carb back on and test so I whipped it off to double check and cleaned it again, running beautifully now.

The primer system being stuck down was the issue I'm sure as testing again and holding primer plunger down re-creates the symptons.

I think the reason it did this after running fine on the sea previously was that when flushing and running dry at the last moment to clear as much fuel from the carb I pull the choke out until it finally dies, this being held in together with a few years of varnish/crud must have meant it chose that moment to stick down, hence the issues the other day and three weeks later

I've got the mixture screw where it seems happiest running between too rich and too lean (about 1 1/4 turns out) and killed/re-started a dozen times - running very nice now so fingers crossed for the next trip.



Thanks again to all for the input.

[uncle al]

the plunger is for cold start,not like I said an accelerater pump.My half brain cell was asleep sorry. when you pull the knob out it debresses the plunger that sqirts a little extra fuel into the carb for an easy start. setting it is all part of the setup and sychronizing , timming revs etc,If it was my obm,I wouldnt run the idle air mixture on less that one and a half out from lightly seated.The fuel mix I would use is a fifty to one mix, I know it will be a little oily , but better that than not enough oil.

[Max...]

Thanks again Al, ran perfectly on a run Thursday and we had a great time (pic below). I'm out of my 'Victor Meldrew' mood now and just pleased I know exactly why/what caused it and the issue is fixed rather than being a random unexplained problem - ie the worst type of all! Had the tacho on it and it seemed pretty well set up hitting 5750 at WOT and running smoothly and quietly (for a 2 smoke)...

[Trimix]

Thats great news. Btw, you look a lot younger than I imagined

[Pikey Dave]

Originally Posted by Max...

I've got the mixture screw where it seems happiest running between too rich and too lean (about 1 1/4 turns out) and killed/re-started a dozen times - running very nice now so fingers crossed for the next trip.



Thanks again to all for the input.

I'd always err to the rich end rather than lean, you don't want to run a 2 stroke lean.

[Max...]

Originally Posted by Trimix

Thats great news. Btw, you look a lot younger than I imagined

I wish! Only to be eleven again...

[sparky666]

Result

[Chasbroon]

Almost certainly a blocked pilot jet. Easily sorted.

[Max...]

Just bumping this up again as a minor warning to anyone else with one of these to check - got my engine out for pre-season checks and the little blue plunger was stuck solid once again - see this post on page 3:

http://www.rib.net/forum/f36/reachin...tml#post631280

Dismantled it completely this time and cleaned the bore for the plunger with a thin rod wrapped in 1200 grade oiled w&d, polished the plunger and reassembled with a dose of silicone grease and a nice tight fitting rubber nipple thingy I found to slip over the plunger and carb mount again filled with silicone grease - this should keep the salt water out and keep it all running silky smooth again.