Mariner 15 2 Stroke running too fast!

[LanceB]

Hello All,

I'm new to the forum & have looked through the post but can't find a reference to my particular engine issue. I purchased a Mariner 15M 1997 year 2 stroke recently - actually it was included in the sale of a Honwave T32 & Honda BF5 package. It was sold as not running when brought out for the spring this year.

I knew I was taking a chance on it but you have to sometimes I guess. I cleaned it up, changed the plugs, cleaned the fuel out & cleaned the filter.

It started first time so I was really chuffed & started pumping water after the thermosat opened up!!

The problem though is that it's actually running too fast - it doesn't seem to want to run at anything like tickover or slow speed even tough I turned the primer knob fully counter clockwise. The owners manual said screw the slow idle screw full in on the carb & then back it out 1.5 turns, which I did. Any other adjustment screws have a red paint on them to lock them in place I assume so I left them well alone.

Is there any adjustment anyone can suggest I try?

Thanks in advance

[oujakov]

When you're playing with idle screw, does the motor respond (increasing rpms)?
Or does it start to respond only when the idle screw is more than 1.5 turns in?

1. It is possible the throttle might be stuck in the semi open position. See if the throttle cable is in fully closed "off" position. Try lublicating it with wd40 or similar.
2. If hasn't helped, take carb off and see if the butterfly can be freely be opened and closed. While you're at it, get the carb fully cleaned in the with the toothbrush and gasoline. Get you tire inflator running, set it up with the soccer ball inflating needle and get all jets and all possible channels air pressure cleaned.

[LanceB]

Thanks oujakov for your advise - I had a thought about the slow idle srew this morning. The maunual said turn fully clockwise & then back out 1 1/2 turns.

The screw is slotted & I assumed 1 turn was 365 degrees from a point on the circumference of the screw. Was I right or is it just a 180 degree turn of he screw driver?

Could to many turns anticlockwise (out) be the cause do you think?

Will cerlook at cleaning the carb out as you suggest if it isn't jus a miss understanding of terms on my part.

[LanceB]

Hope you got the idea - meant to say 360 degrees etc

Forums don't have spell check either of course!!! :-)

[Bigmuz7]

Originally Posted by LanceB

Hope you got the idea - meant to say 360 degrees etc

Forums don't have spell check either of course!!! :-)

Yes it does .. top right of your post box its the ABC with a tick under it .. wont help you with numbers though

[oujakov]

Originally Posted by LanceB

Thanks oujakov for your advise - I had a thought about the slow idle srew this morning. The maunual said turn fully clockwise & then back out 1 1/2 turns.

The screw is slotted & I assumed 1 turn was 365 degrees from a point on the circumference of the screw. Was I right or is it just a 180 degree turn of he screw driver?

Could to many turns anticlockwise (out) be the cause do you think?

Will cerlook at cleaning the carb out as you suggest if it isn't jus a miss understanding of terms on my part.

Idle screw is nothing more than the "fine throttle" at the closed position of the carb's butterfly. You screw the adjustment in - you're opening the throttle, means motor starts to run faster, and vise versa.
There is no "set" position for this idle screw. Play with it until the needed speed of the motor at idle "starts licking" your ear.
I've always cleaned my carbs with gasoline, disel fuel or kerosene.

Try doing something tonight and then post results.

[LanceB]

Originally Posted by oujakov

Idle screw is nothing more than the "fine throttle" at the closed position of the carb's butterfly. You screw the adjustment in - you're opening the throttle, means motor starts to run faster, and vise versa.
There is no "set" position for this idle screw. Play with it until the needed speed of the motor at idle "starts licking" your ear.
I've always cleaned my carbs with gasoline, disel fuel or kerosene.

Try doing something tonight and then post results.

Thanks for that - i'll see if I can try it tonight (depends if the rain holds off) & post results

Cheers

[m chappelow]

could it be drawing air in, from loose nuts or a broken gasket on the carb where it mates to the engine ,

[LanceB]

Originally Posted by m chappelow

could it be drawing air in, from loose nuts or a broken gasket on the carb where it mates to the engine ,

Not sure but everything looks Ok. I'm going to give it another go tonight if possible & another good look over myself. May have to take it somewhere if not

[AllenF]

when you adjust the screw rev the engine slightly then WAIT it takes a bit of time to use the fuel alredy there
1 turn is a full 360 but full in (to a pinch tight) then two out is a VERY good place to start from