Fuel line diameter for 85HP

[BluejayII]

1988 Force 85HP, what diameter fuel line should I be using. I had 5/16 but when I went to replace it the local marina mechanic gave me an anti siphon valve for the inboard fuel tank(had a quick disconnect on it), 3/8 hose, primer bulb and all new fittings. Now I have issues with motor not wanting to run at WOT for very long before dying out(primer bulb will be soft). I had added a water separator filter a couple of years ago. I have cleaned carbs and reset them using the very good guidelines I found on this forum. I have a tach on order from I boats to make sure my idle rpm is set correct. All cylinders have spark and compression is #1-135, #2-135, #3-140, this was before I ran some seafoam deep creep thru carbs. I also have replaced the fuel pump diaphragm. Thank you or any assistance.

 

[SkiDad]

3/8 should be fine - i think a lot of guys run that size - i have 1/4 on mine in most spots. I think you need to make sure your running good clamps, not the spring kind, but the ones that tighten. I wonder if it's that anti-siphon valve, can you take that off for a bit ?

Does the primer bulb get hard and stay hard before you start the engine ? I hear that you can have someone squeeze the primer bulb while going fast and if that helps it means you had a problem in that line. I know Jiggz, Frank and others will probably be along with more helpful advice.

 

[jerryjerry05]

NO anti-siphon valve on an outboard.
The fuel pump isn't strong enough to pull past it.
Remove it.You'll run a lot better.
The 88/85 came with1/4in hose.
What you can put in a fuel line.
A water/fuel separating filter.
A small filter between the pump and carb.Wally World G-2 or G-12

 

[BluejayII]

Thanks for the info. I will remove the anti-siphon valve and replace it with the quick dissconnect style that was on there.
Should I replace the fuel line with smaller diameter before taking it out to test?

 

[NYBo]

I'm pretty sure mine is 5/16".

 

[gregmsr]

On my 125 HP I had 5/16 but installed new 1/4".
Runs like a champ.......

 

[jerryjerry05]

The size shouldn't matter.

 

[BluejayII]

Thank you all for your input, I will remove the anti-siphon valve and am planning a weekend trip to the lake sometime next month(last camping trip of the year).
I will post the results when I return.