40 hp 2 stroke

popeyethesailor · 22 March 2015, 17:17

Just a general question
Would you consider it normal for a mariner 2 stroke 40 to be a little 'lumpy' at idle?
Before I go and take the carb apart to give it a good clean which I am a bit reluctant to at the min as I am taking it out for the first time in a few weeks and it is working just a little lumpy at the mo
I will try and put a video up
Thanks in advance

Last Tango · 22 March 2015, 17:27

Hi

If you're running it on muffs and a hose it'll "spit and fart" a bit. If you can get it in a test tank that's deep enough to replicate the depth that the engine will be at on the back of the boat you'll get a better idea but don't expect it to be silky smooth. Two strokes don't like idling.

popeyethesailor · 22 March 2015, 17:34

http://youtu.be/7gU3I4d9Cd8

Last Tango · 22 March 2015, 17:36

Maybe idling a bit slow but sounds ok.

popeyethesailor · 22 March 2015, 17:36

Quote:

Originally Posted by Last Tango

Hi

If you're running it on muffs and a hose it'll "spit and fart" a bit. If you can get it in a test tank that's deep enough to replicate the depth that the engine will be at on the back of the boat you'll get a better idea but don't expect it to be silky smooth. Two strokes don't like idling.

Hi thanks for that I have had it in a tank today and re adjusted the mixture and sprayed some carb cleaner in and maybe slightly better then in this vid

popeyethesailor · 22 March 2015, 17:49

Quote:

Originally Posted by Last Tango

Maybe idling a bit slow but sounds ok.

Hi thanks I have increased the idle a little more it sounds better just goes into gear like farmer Johns tractor lol

jeffstevens763@g · 22 March 2015, 17:58

Quote:

Originally Posted by popeyethesailor

Just a general question
Would you consider it normal for a mariner 2 stroke 40 to be a little 'lumpy' at idle?
Before I go and take the carb apart to give it a good clean which I am a bit reluctant to at the min as I am taking it out for the first time in a few weeks and it is working just a little lumpy at the mo
I will try and put a video up
Thanks in advance

I had a mariner 40 some years ago yours sounds ok to me mine throbbed a bit on tick over, they use to say there's only two throttle positions for a two stroke wide open and off.
Recently had an old Johnson 15hp throbbed on tick over the same sweet as when you opened her up.
I think gurnard runs a mariner 40 pm him Popeye.

Last Tango · 22 March 2015, 18:10

Yep. they make a fair crack going into gear on the muffs but it'll be fine once it's in the water. Not 100% sure about your specific engine but the norm is to adjust idle speed with the engine propelling the boat in the water. However if it's to low it'll stall when you put it in gear and if it's to high it'll "kick hard" when it goes into gear and it'll be difficult to pull back into neutral................really, if it sounds right it probably is right.

JamesF · 22 March 2015, 19:21

We've run the Mercury-badged version of that engine for years, and currently have two of them on SR4s. Both the current ones and the previous pair were exactly like that at idle. It's a two-stroke twin after all. It's a little smoother on the water, but it'll still kick a bit. All quite normal.

Going into gear tends to sound a bit agricultural, but that's normal too. It's better if you don't hesitate, just drop it straight in. There's quite a nice, positive change in resistance between selecting a gear and picking up the throttle — at least on ours — so it's quite easy to do. The couple of Yamaha and Honda throttle units I've used had a narrower idle 'detent', which was a bit harder to use.

A1an · 22 March 2015, 19:51

Idle should really be setup with the leg in water so it has the correct back pressure.

Some manufacturers state that idle should be set with the leg in water AND in fwd gear.

Nos4r2 · 22 March 2015, 19:53

Quote:

Originally Posted by A1an

Idle should really be setup with the leg in water so you are setting it up with the correct back pressure.

Some manufacturers state that idle should be set with the leg in water AND in fwd gear.

Seconded. It sounded ok to me in the vid, should have left it at the same tickover and tried it out afloat before changing idle speed.

popeyethesailor · 22 March 2015, 20:46

Quote:

Originally Posted by A1an

Idle should really be setup with the leg in water so it has the correct back pressure.

Some manufacturers state that idle should be set with the leg in water AND in fwd gear.

Yep that makes sense thanks

popeyethesailor · 22 March 2015, 20:47

Quote:

Originally Posted by JamesF

We've run the Mercury-badged version of that engine for years, and currently have two of them on SR4s. Both the current ones and the previous pair were exactly like that at idle. It's a two-stroke twin after all. It's a little smoother on the water, but it'll still kick a bit. All quite normal.

Going into gear tends to sound a bit agricultural, but that's normal too. It's better if you don't hesitate, just drop it straight in. There's quite a nice, positive change in resistance between selecting a gear and picking up the throttle — at least on ours — so it's quite easy to do. The couple of Yamaha and Honda throttle units I've used had a narrower idle 'detent', which was a bit harder to use.

Thanks James

JamesF · 22 March 2015, 23:49

I don't know how they compare to the RIBnet favourite Yamaha two-strokes, but I like them.

dave3235 · 23 March 2015, 00:50

Hi all

If you have a tach put it on,850 rpm's in gear 950 out of gear.Shouldn't be to far off or check themail manual.

uncle al · 23 March 2015, 14:52

if I remember correctly yours is the two cyl, single carb. If you set it up at eight hundred rpm or slightly higher in fwd gear, and the idle air mixture one and a half turns out from lightly seated , you wont be far out on your settings, when set up correctly there should be about a two hundred rpm differance between in gear and nutrual .