fuel line size

[zzimmer3]

on my 1989 mariner 75hp, the fitting that connects to the motor requires a 5/16" hose, the built in tank and current fuel line with in line primer bulb is 1/4", is there a problem installing an adapter after the bulb? will it cause any fuel shortage problems? or should i change the fitting at the tank and all the lines and primer bulb to 5/16" line? thank you for your help.

 

[Maxz695]

Re: fuel line size

I bought the wrong primer bulb. It was 1/4 and I had 3/8ths line on both ends. It would not get or stay hard I had mega problems that day the bulb being one of them I returned it and got the proper 3/8ths one and it works beautifly now. I would go with the size of the fitting on the motor from the tank to the bulb at least and then to the engine where after the quick disconnect it runs 1/4 line then on.

 

[zzimmer3]

Re: fuel line size

that sounds like good advice, thank you. i'll swap over to 5/16 on the whole thing.

 

[ajgraz]

Re: fuel line size

I agree with 5/16" throughout. Since you're revamping the fuel system, definitely get ethanol-friendly lines and bulb, and also a good time to think about adding a fuel/water separator filter if you don't already have one.

 

[zzimmer3]

Re: fuel line size

I never thought of adding a seperator, but thats a good idea, i'm going shopping this weekend, I'll add that to the list. that'll save me some trouble in the future. (my dad has suffered from not having one on his boat a couple times i've been w him). thanks

 

[ajgraz]

Re: fuel line size

I've got the 21 micron Sierra separator kit on my Merc 70hp 1978, the one that's like under $30 and the filter looks like a spin-on oil filter. Since installing it, I have not had any of the old "crap fuel" gummed lines / carbs issues I always used to get. I love it.

 

[zzimmer3]

Re: fuel line size

i'm going to the 'boat' store tomorrow, thank you for the tip