Mercury 2 stroke bogs down

[Courageous]

Hi chaps, been having ongoing issues with my (approx) year 2000 carb'd Merc 150 stroker. We have had water in the fuel tank and to be honest I put most of the subsequent issues down to that. Avoided removing the carbs for a clean and have that on the list to do but the other day the engine started doing something it hadn't done before which has me thinking differently. At WOT the engine was dieing then picking up but without any control input. The thing is the tacho wasn't dropping with it but remaining at the WOT rpm which I believe indicates an electrical problem. Would anyone have any idea as to which component might cause this? I know from Uncle Al explaining to me that the tacho remains at the rpm at which the engine was shut down so I am assuming this will be an ignition problem.

All help and opinions appreciated.

[yam man]

Originally Posted by Courageous

Hi chaps, been having ongoing issues with my (approx) year 2000 carb'd Merc 150 stroker. We have had water in the fuel tank and to be honest I put most of the subsequent issues down to that. Avoided removing the carbs for a clean and have that on the list to do but the other day the engine started doing something it hadn't done before which has me thinking differently. At WOT the engine was dieing then picking up but without any control input. The thing is the tacho wasn't dropping with it but remaining at the WOT rpm which I believe indicates an electrical problem. Would anyone have any idea as to which component might cause this? I know from Uncle Al explaining to me that the tacho remains at the rpm at which the engine was shut down so I am assuming this will be an ignition problem.

All help and opinions appreciated.

Sound like carb trouble to me. most probably the bottom carb were the crap always falls

[Courageous]

Ok Yam Man but would that not show up on the tacho?

[Peter_C]

Fix the known issue (The carbs) then report back how it runs. Pointless to try to diagnose anything until the first issue is resolved.

Edit: Also make sure the water is no longer a problem in the fuel tank, and put a water separating fuel filter inline.

[Turbodiesel]

Sounds like water in the float chambers to me. As the engine runs at WOT it drains the float chambers of fuel until the water that sits at the bottom gets drawn up causing the engine to bog this then give the carbs the chance to fill back up with fuel and your away again until you drain the carbs of fuel on the next wot run. You cant get all the water out just by opening the drains on the carbs.

[Courageous]

Yep, can relate to all this but why would the tacho not respond?

[Turbodiesel]

Originally Posted by Courageous

Yep, can relate to all this but why would the tacho not respond?

No idea!!!

[Courageous]

.... could be more than one issue then. Ok time to strip carbs then.