Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

kippstakes

Petty Officer 2nd Class
Joined
Jun 10, 2013
Messages
117
Motor was running very rough- had not had it on the water yet, new used engine. Carbs sparkling and good compression. Took it to shop and they installed new plugs/caps, set the carbs, and did a bit of wiring-- seemed to be running like a top.. out of the water.
Next day took her out and when I popped into gear and gave it juice, the engine bogged down and wouldn't do more than maybe 5 knots wide open, and was also guzzling gas. Drained both carb bowls on the spot and pumped some fresh gas in, ran a bit better, but not by much and only for a mile or so, and then right back to slow motion.
I'm concerned about how much oil I added, seemed like a lot.
A 50:1 ratio is what I've heard is correct.
The equation I used is:

128 (oz/gal) x 1/50 (or .02, for the ratio) x gallons of un-oiled, nonethanol gas

So in the end I topped the tank off to about 5 gal and ended up putting about 14 oz of oil in.
Seemed like a bit much, but I'm pretty sure my math is correct.

Suggestions??

Thank you
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

50/1 is good. I work in litres/mls so I cant do the conversion on that to gallon ozs.

Check you have spark on all cylinders and if so check compression next.
Pull out your plugs and look for any abnormailities and difference between them in colour
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

Yes thanks to the internets computer brain 5gallons should have about 14oz i it.
It does seem a lot but is correct
Check that with the engine off that the primer bulb stays firm, ie so no fuel is leaking past carb valves into engine
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

Do a cylinder drop test on it to see if it's running on both cylinders or not.
 

pn

Petty Officer 1st Class
Joined
Apr 20, 2013
Messages
374
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

sometimes the fuel pump sucks gas in through the pulse line givin a super rich condition. take a look at your fp diaphram.
 

kippstakes

Petty Officer 2nd Class
Joined
Jun 10, 2013
Messages
117
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

Thank you
what should i be looking for on the diaphragm?
 

pn

Petty Officer 1st Class
Joined
Apr 20, 2013
Messages
374
Re: Oil/gas ratio correct? 72 50hp Evinrude bogging down bad.

update with what you have done. fp diaphram is not cracked rotted, stretched, pin holed, dried out, compramised, or marginalizied
 
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