Question about primer bulbs

[hhopkins]

I have a Johnson 115 OB on a 24 foot pontoon boat and of course I have a primer bulb to squeeze for the first start of every day. I have learned that I almost never really need to use the primer bulb. I friend of mine has an Evenrude 115 IO in a 17 foot runabout which he tells me is the same power head as mine and he does not have a primer bulb. We both have fixed fuel tanks. Why does the IO not need the primer bulb installed?

 

[OBJ]

Re: Question about primer bulbs

Position of the engine is the reason. Because your outboard sets high above the fuel tank, you need a way to get the fuel started to the engine, thus the primer bulb. The bulb has two one way valves that keeps the fuel from running back to the tank.<br /><br />Your friends engine, which I'm assuming is a squirt boat, sets low in the hold and gravity keeps the fuel coming to the engine so a primer is not really needed.

 

[hhopkins]

Re: Question about primer bulbs

Thanks OB Jim - That probably also explains why I never need to prime mine - because in my configuration the tank is above the engine.<br /><br />Emerson