Symptoms of a Fuel Air Leak

zibzer

Petty Officer 2nd Class
Joined
Apr 28, 2007
Messages
114
Hello, Noticed the other day that when a prime the bulb on my 1979 Evinrude 100hp that gas shoots out the connector to the engine once the bulb gets firm. Engine seems to be running OK (maybe a little slower than it should but it was choppy so hard to tell). However, I will fix with new o-ring ASAP.

But then i got to wondering would a leak like that cause the engine to act up at idle, WOT, or everywhere? Also, what would the symptoms be exactly? Thanks for the input!
 

Fuzzytbay

Chief Petty Officer
Joined
Jun 6, 2008
Messages
557
Re: Symptoms of a Fuel Air Leak

Air leaks can be problimatic of many symptoms. Depends upon the engine, and type of carberation used. Side bowl carbs do not take well to an air leak, bottom bowls are move forgiving. Keep in mind extra air in the fuel system leads to leaner running, which can lead to melted piston crowns, or worse.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
27,701
Re: Symptoms of a Fuel Air Leak

Hello, Noticed the other day that when a prime the bulb on my 1979 Evinrude 100hp that gas shoots out the connector to the engine once the bulb gets firm. Engine seems to be running OK (maybe a little slower than it should but it was choppy so hard to tell). However, I will fix with new o-ring ASAP.

But then i got to wondering would a leak like that cause the engine to act up at idle, WOT, or everywhere? Also, what would the symptoms be exactly? Thanks for the input!

Since it is easier for the fuel pump to suck air than it is for it to lift fuel, the symptoms would be a lack of adequate fuel to the carburetor. Of course that could result in cutting out, quitting, snezing, lack of power, etc. Yes, in theory, it could cause engine damage, but you probably would be fixing it before it got that bad (hopefully).
 
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