primer bulb location

[fishkiller]

when replacing your fuel line do you want the primer bulb closer to the engine or the tank or in the middle? my new boat(or shall I say new 'old' boat) didn't have a fuel line on it and I was getting ready to plumb.....also should you use something like 'instead of lead' in your mix with the gas and oil or is the oil good enough these days to go with the unleaded for my 30 year old outboard that used to run on leaded regular.thanks

 

[ZmOz]

Re: primer bulb location

It would probably be best to have the bulb closest to the motor. No, don't use any lead substitute...lead was only to lubricate the valves, which your 2 stroke outboard doesn't have.

 

[Solittle]

Re: primer bulb location

It dosen't make much difference where you put the primer bulb so long as it is verticle when you squeeze it (with the to tank end at the top).<br /><br />As for fuel use regular 87 octane with no additives and I strongly recommend that you have a fuel filter/water seperator in the fuel line.

 

[ZmOz]

Re: primer bulb location

Originally posted by SoLittle:<br />As for fuel use regular 87 octane

Depends on the outboard...most 30 year old outboards were designed to run on 90 octane regular...

 

[umblecumbuz]

Re: primer bulb location

The bulb.<br /><br />It is a suction pump, hand operated. All bivalve suction pumps will push liquid better than they pull it. On this basis, putting the bulb closer to the source of the liquid makes it more efficient.<br /><br />Put it nearer to the tank if you have a choice, and prime it in the vertical plane when you pump it.<br /><br />Having said that, the fuel bulb has plenty of spare 'pulling' capacity, so it ain't that critical unless you've got a very long boat with the tank in the bows.

 

[Dan H.]

Re: primer bulb location

After reading this thread I beagn to realize the possible source of a problem that has plagued my early eighties mercury 50hp. The motor has been difficult to start ever since I got it 10 years ago. Runs great! Starts terrible! I've always suspected it was a fuel problem of some kind. Even replaced the "bulb" at one point.<br /><br />The 50 is mounted to my homebuilt skiff. The tanks are built in custom made and mounted amidship.The fuel lines are routed under the floor boards, up to a valve, through a seperator, into the "bulb" which rests across the back deck putting it about 7 feet from the source,and into the motor. Is there something wrong with this setup? Any ideas as to why it takes a magician to start this old motor?

 

[BoatBuoy]

Re: primer bulb location

Originally posted by ZmOz:<br />

Originally posted by SoLittle:<br />As for fuel use regular 87 octane

Depends on the outboard...most 30 year old outboards were designed to run on 90 octane regular...

Hmm. My '77 Evinrud manual says 86 octane, my '56 Johnson manual doesn't say.

 

[gss036]

Re: primer bulb location

Dan, as long as you can pump the bulb and it gets firm, should be working properly. It works best if vertical, rather than horizonal. I would more concerned that maybe your choke is not working.

 

[NC22]

Re: primer bulb location

Sorry about jumping this thread, but I didnt want to start another one on the same subject. Why is vertical better than horizontal?

 

[umblecumbuz]

Re: primer bulb location

Nutcup,<br /><br />Because gravity helps the valves in the pump to close when it's vertical.<br />Try it both ways next time - sometimes you can feel the difference.

 

[Boilermaker]

Re: primer bulb location

Originally posted by SoLittle:<br /> It dosen't make much difference where you put the primer bulb so long as it is verticle when you squeeze it (with the to tank end at the top).<br />

My understanding is that the outlet side should be "on top". The arrow pointing up as you prime.<br /><br /> As for why to prime with the bulb vertical>>>It also helps to get the air out of the fuel line quicker if the bulb is held vertically>>>the air goes to the top of the fuel & out the bulb on the first or second squeeze.<br /><br /> Also>>>I don't remember ANY regular gasoline from 30 years ago having an octane rating of 90???<br />

 

[umblecumbuz]

Re: primer bulb location

Boilermaker, you're right.<br /><br />The outlet end - to motor, not to tank - should be at the top.

 

[NC22]

Re: primer bulb location

Thanks for the info guys. Im having the same problem as Dan H. with my 25 hp Johnson. I have my fuel hose and prime bulb laying horizontal on top of the gas tank now and will try the vertical method next time I'm out with it. Thanks again guys.

 

[gss036]

Re: primer bulb location

http://continuouswave.com/whaler/reference/primer.html <br />Jump over and read this article on primer bulbs, good educational article and will remove a lot of confusion for proper installation.