80,s 70 hp. Mariner rich/lean

[remmer38]

I have a Late 80's?? 70 hp mariner that has a new fuel pump, cleaned carbs, new starter. I have the needles set at 2 and a half turns. When I idle its fine though I had to set the idle screw up a bit. When I give it the juice it has to "catch up" and will after a few seconds. I think I heard a detonation sound earlier. Can anyone help? I havent even seen a post on here for a 70. I have read almost all of em Compression is all up in the mid 130's. My outboard man isnt very good with time management so Ive been doing all the work. So I am asking about the richness/leanness of this strong motor. Thabks in advance<br />R Emmer

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

I am just looking for the needle settings is all. Can someone help?

 

[Clams Canino]

Re: 80,s 70 hp. Mariner rich/lean

Is this the three cylinder ?<br /><br />-W

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Yessir. 3 cylinder. I appreciate your attention.<br />Addendum to above. I live on the water and take her out every day. I will try to explain my concerns. Does turning the needle valve on the carb in richin or lean? I idle no problem, start no problem, shift with no stalls, run smooth at mid speed. Going to power it almost has that sound of a spark plug kicking in. Running at full throttle tonight I found it was "missing" a bit. Throttling back down to mid she seems to run fine and smooth. I havent changed the plugs yet but they sure looked new when I looked. I am theorizing:<br />1) When I got the carbs back from the mech, he had the needles at 1 3/4 turns out. I saw a post where someone with a similiar engine had em at 2 1/2. It runs better out there at 2.5. So wrong needle position??<br />2) Bad plugs? I would sure feel dumber if that were the case.<br />As I said earlier any help would be great and appreciated.<br />"A bad day of fishing is better than a good day at work"

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

"plug kicking in. Running at full throttle tonight I found it was "missing" a bit. Throttling back down to mid she seems to run fine and smooth. I havent changed the plugs yet but they sure looked new when I looked. I am theorizing:"<br /><br />Yes I said tonight.

 

[Clams Canino]

Re: 80,s 70 hp. Mariner rich/lean

2 1/2 out outta be plenty rich enough, if you get a good hole shot - it is.<br /><br />1st thought is that it's fuel starving at top end. Might wanna check the fuel system tank to carbs and make sure it's all clean and free flowing.<br /><br />It can't hurt to clean the dist. cap and change the plugs out to be sure too.<br /><br />-W

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Thanks Clams. So turning in is richening? Im thinking its opposite of what I think. In is more air? And you are thinking that my fuel system sucks air (literally)? Im getting new plugs today. Ill keep ya informed. Distributure cap? Aint got one of those. CD ignition. Happy Sunday. Its a beautiful day.

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Plugs didnt change the behavior

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Well I see the experts really arent all that helpful. A simple question about needle valve placement. Thanks bunches for the free advice. Thats right , nothing in life is free anymore. Have a good day.

 

[dilligafda]

Re: 80,s 70 hp. Mariner rich/lean

Originally posted by remmer38:<br />Well I see the experts really arent all that helpful. A simple question about needle valve placement. Thanks bunches for the free advice. Thats right , nothing in life is free anymore. Have a good day.

Well, some experts take a day off every now and then. <br /><br />Turning the mixture screws in will lean the carb out at idle. It has little to no effect on the wide open operation. As Clams said, 2-1/2 turns out from light seat should be plenty. Have you checked out the fuel system yet. I agree that it sounds like the engine is starving for fuel at wide open. Check the throttle plates at wide open and make sure that they aren't going over center. Also make sure that the linkages are setup correctly. Let us know what you find out.

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Thanks sir. I am going to change fuel line and vac hoses to fuel pump. I hear what you and clams are saying about the high end and it makes sense. Especially when she idles and mids with authority. Does fuel line size matter? I could go to a smaller diameter line if you think that would help. Maybe it is the fact there is no air filter. I think unlikely but Im no expert.<br />Thanks<br />Oh serial number 6073724

 

[dilligafda]

Re: 80,s 70 hp. Mariner rich/lean

Yes, size does matter (according to some women I know ) Do not go to a smaller line, it will restrict the fuel more and create a lean condition. Minimum size should be 5/16, but 3/8 will suit you the best for that motor. <br /><br />Good luck!

 

[SpinnerBait_Nut]

Re: 80,s 70 hp. Mariner rich/lean

remmer38, not that it will make much difference, but you are correct on your serial number it is not an late 80's it is a early 80 model.<br />70 5888279 - 6104269 1981

 

[remmer38]

Re: 80,s 70 hp. Mariner rich/lean

Yes its a 1981. I finally interprutated(sp?) the german site for serial numbers. I was doing fine it but I have to report she now feels like shes on half throttle at WOT. Ive got good spark..nice and blue. She has no prob starting goin in gear, nice idle characteristics. I quess Im gonna have to go wait my turn here for mech to even look He aint the quickest. Im starting to think Ive missed something. Ive done the fuel system good. As i said before, she used to have to catch up to the throttle. I throttle up slow(not the hole shot type of go) it would just climb out and get. Timing problems? I fish close to home almost everyday cause there are lots of em. I just coast out a few hundreds yards from home and Im on Reds, Trout, Sheephead, kittycat fish(good chum) and one incredible sunset. I really appreciate all the help you boys have and are providing. Cheers Mate