Hello guys,
I can't seem to get any good ideas through swedish forums, so i thought I'd give it a go here. I hope you guys can help me out.
The engine
Mariner 30hp 2-stroke, probably late 80's or early 90's, single carburettor, two cylinders.
Starts fine, idles fine but won't rev more than 2500-3000rpm. Ran fine a couple of days ago, but suddenly started doing this. Won't rev even in neutral with the idle throttle, so it's not a prop problem. It acts like its got a rev limiter and stays steadily at low revs. The only way to rev it higher is if I take the cover off and open the throttle manually on the carburettor.
I checked the throttle and gear wires/cables and all is good. Everything moves like it should, including the ignition plate.
Changed the spark plugs today hoping one of them was acting up, but no difference. Old plugs were a bit black and wet, telling me it's running a little rich. After changing the spark plugs i tried pulling the top coil, and it continued idling on the lower cylinder. It did not however idle on the top cylinder. I have yet to do a carb cleaning and compression test. I will also try swapping the coil leads to see if it starts firing on the top cylinder.
I just think it shouldn't be able to rev normally when i manually open the throttle on the carb if it's a carb problem. Before i start spending money on parts i wanna cover all basic fixes first.
So, really, i know i still have a few things to try before writing this post, but i was hoping i could get more advice on things to try. I'll get back to you guys tomorrow when I've tried the things above.
I can't seem to get any good ideas through swedish forums, so i thought I'd give it a go here. I hope you guys can help me out.
The engine
Mariner 30hp 2-stroke, probably late 80's or early 90's, single carburettor, two cylinders.
Starts fine, idles fine but won't rev more than 2500-3000rpm. Ran fine a couple of days ago, but suddenly started doing this. Won't rev even in neutral with the idle throttle, so it's not a prop problem. It acts like its got a rev limiter and stays steadily at low revs. The only way to rev it higher is if I take the cover off and open the throttle manually on the carburettor.
I checked the throttle and gear wires/cables and all is good. Everything moves like it should, including the ignition plate.
Changed the spark plugs today hoping one of them was acting up, but no difference. Old plugs were a bit black and wet, telling me it's running a little rich. After changing the spark plugs i tried pulling the top coil, and it continued idling on the lower cylinder. It did not however idle on the top cylinder. I have yet to do a carb cleaning and compression test. I will also try swapping the coil leads to see if it starts firing on the top cylinder.
I just think it shouldn't be able to rev normally when i manually open the throttle on the carb if it's a carb problem. Before i start spending money on parts i wanna cover all basic fixes first.
So, really, i know i still have a few things to try before writing this post, but i was hoping i could get more advice on things to try. I'll get back to you guys tomorrow when I've tried the things above.
