'86 Classic 50 Idle issues. HELP ME!!

Q_ball

Seaman
Joined
Mar 26, 2009
Messages
61
I've finaly got my restoration done but still having problems getting my motor to purr. I cannot get it to idle smooth below 900-1000rpm's while in a test tank. Idle time should be 5 ATDC but it struggles after 0 degrees. Ive done the carbs, fuel pump,new plugs, stator and trigger, rectifier, switch box. When I picked this motor up it had burned wires from the stator to the rectifier so i decided to replace everything and keep the parts that were still good as spares but only the switch box checked out good.
Ive been trying to set the ide mixture and timming but not getting rpm's low enough. it also stalls when shifting if my rpms are below 1000 (a little hard on my gears). The mid and high range are fine, infact I'm planning at 30mph but hitting 6300 and have to back off until i fine tune my prop selection.

where to go from here?:facepalm:


1972 15' tri-hull (flat hull at stern)
1986 45hp classic 50 SN OB109990
compression
#1 100
#2 100
#3 100
#4 92
floats set at 1/4
Elevation 4500 ft
 
M

Maxz695

Guest
Re: '86 Classic 50 Idle issues. HELP ME!!

Compression s a bit low try some decarb it should help free up the gunk in the rings
 

Q_ball

Seaman
Joined
Mar 26, 2009
Messages
61
Re: '86 Classic 50 Idle issues. HELP ME!!

The top of the pistons had alot of carbon build up on them. I had heard good results from seafoam, so i tried that tonight and WOW the junk that came out was nasty. I'm going to run it more in the morning to finish cleaning it out and try to re-adjust and check compression again.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: '86 Classic 50 Idle issues. HELP ME!!

Floats at 1/4?

With the carb inverted the floats should be parallel to the carb body, low floats can make idle mixture difficult to adjust perfect.
 

Q_ball

Seaman
Joined
Mar 26, 2009
Messages
61
Re: '86 Classic 50 Idle issues. HELP ME!!

My Clymer manaul says it "should be 1/4 +-1/64 from float bottom casting" which does end up being parallel. I didn't check them when I rebuilt the carbs but did pull them back off to check and the bottom carb was really low which I think was why that carb would bleed a little fuel out of the front.

I'm going out to check my ignition coils. All of them have spark but I want to check how strong the spark is using an adjustable spark tester. Anyone know how far the spark should jump? I read on another post 3/16 but not sure.
 

Q_ball

Seaman
Joined
Mar 26, 2009
Messages
61
Re: '86 Classic 50 Idle issues. HELP ME!!

I found the post and it was from you CharlieB! You said 7/16 not 3/16. glad I found it again.
 
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