2 Stroke Outboard Help

GTM · 19 April 2009, 19:37

Hi all,

Sorry if my questions are abit ignorant, but hoping someone can help

I've got a 2 stroke 8hp Mariner outboard, and it hasunt been run since last summer. Last summer it performed well when it was going, first few times it was quite happy to start, but it never likes to idel, even when warm you have to be lucky for it not too cutt out, and when it does its a pain to get started again.... ?

I'm quite mechanicaly minded and enjoy thinkering with my cars, can anyone tell me the service procedure on a 2 stroke outboard? I'ed like to have ago myself, What I should look for, change, clean and so on. The first things that strike me are things like Sparkplug, HT Lead, Coil, Fuel Filter, Air Filter, Carb (I asume it would have a pot you could clean out like anyother 2 stroke carb?) Carb jet?

Also can you "tune" a 2 stroke outboard for more power, or are outboards not like that at all? (I think I've heard changing th prop can improve performance on boats?)

Many thanks!

GTM · 19 April 2009, 20:43

Nothing?

Hightower · 19 April 2009, 21:03

Quote:

Originally Posted by GTM

Hi all,

Sorry if my questions are abit ignorant, but hoping someone can help

I've got a 2 stroke 8hp Mariner outboard, and it hasunt been run since last summer. Last summer it performed well when it was going, first few times it was quite happy to start, but it never likes to idel, even when warm you have to be lucky for it not too cutt out, and when it does its a pain to get started again.... ?

I'm quite mechanicaly minded and enjoy thinkering with my cars, can anyone tell me the service procedure on a 2 stroke outboard? I'ed like to have ago myself, What I should look for, change, clean and so on. The first things that strike me are things like Sparkplug, HT Lead, Coil, Fuel Filter, Air Filter, Carb (I asume it would have a pot you could clean out like anyother 2 stroke carb?) Carb jet?

Also can you "tune" a 2 stroke outboard for more power, or are outboards not like that at all? (I think I've heard changing th prop can improve performance on boats?)

Many thanks!

Spark plugs, fuel filter and gearbox Oil generally only need replacing at regular intervals on low tech 2 stroke outboards. Other frequent duties include greasing all pivots linkages etc with proper marine grade grease. If not already done, check the impellor (cooling pump) in the leg, on the gearbox. If in doubt replace it!

Nothing else really needs to be done unless you're having problems with the engine.

At the end of the season it's worth winterizing the outboard and fogging the cylinder/s and also draining the fuel out of the float chamber as old fuel can varnish the insides that then becomes unstuck and clogges the jets. Perhaps this is what has happened and needs the carb/s stripped and blown out.

The only reliable way of increasing performance if to stick a bigger carb on. As for prop size, I doubt that it would make much difference with 8hp on tap. adjusting the trim would be the first experiment I would try.

Hope this helps.

Chris · 19 April 2009, 21:05

I would start with the Carb if the plugs look ok and you are running fresh fuel.

I have had similar problems and found that giving the carb a glood cleanout and blowing through all the passages and jets solved the problem.

Poly · 19 April 2009, 23:08

Quote:

Originally Posted by GTM

I've got a 2 stroke 8hp Mariner outboard, and it hasunt been run since last summer. Last summer it performed well when it was going, first few times it was quite happy to start, but it never likes to idel, even when warm you have to be lucky for it not too cutt out, and when it does its a pain to get started again.... ?

are you having a specific problem now or just the general one of not liking idle? Unfortunately 2 stroke outboards don't like idling for long periods as the plugs get oiled up - this would also explain the difficult to restart issue (take plugs out and clean if necessary). The solution is not to leave it idling for too long.

GTM · 20 April 2009, 19:21

Its very regular ounce it starts and continues all the time. Only thing that seems to help is the next time it comes out and is used again...

uncle al · 20 April 2009, 20:24

if you would like to ring me tommorrow on 01869 326411,but according to the factory it is illegall (against common market rules)to up rate from what they are sold as eg an 8hp should stay as a 8hp its all to do with emishions also just changing the prop is not usually the answer either

Poly · 20 April 2009, 20:39

Quote:

Originally Posted by uncle al

but according to the factory it is illegall (against common market rules)to up rate from what they are sold as eg an 8hp should stay as a 8hp its all to do with emishions

Al - sounds suspiciously like chinese whispers to me... can you or the "factory" point us to the relevant legislation that says the owner (not seller/manufacturer) of an outboard engine cannot modify it themselves ?

uncle al · 21 April 2009, 07:43

that is what the factory told me as i am not a lawyer i just repair obms i have to take what i am told at face value it is to do with the CE plate and emissions

Poly · 21 April 2009, 09:09

Quote:

Originally Posted by uncle al

that is what the factory told me as i am not a lawyer i just repair obms i have to take what i am told at face value it is to do with the CE plate and emissions

mmm... but there are hundred of things in this world which are supposedly illegal because "someone told me so" and actually are not illegal at all, but possible not company procedure; not approved by the company; or even at a stretch are grey areas. Who's to blame - the guy who started the myth (because it was a quick easy answer to a question) or the guys who perpetuate it to everyone they see?

Manos · 21 April 2009, 11:40

If is not a big bother, can someone say what parts you need to change to modify the 8bhpMariner?
I have asked in the past and my mechanic (Merc/Mariner authorised) said that for the 8bho is not possible.

uncle al · 21 April 2009, 21:08

i need a serial number because there are minor diferances in some obms and major ones in others

Manos · 22 April 2009, 10:32

Mariner 8bhp 2strokes 1998 model Engine serial number 09985493

uncle al · 22 April 2009, 18:54

i have checked today it would be better to buy a new obm as it would be under guarantee where as if you replaced the p/h and carb at the end of the day you still have a 1997 model year obm