Fuel delivery on mercruiser I/O

[Fishtails]

Hey guys....I have a question for you.

I had the boat out yesterday and I'm having a fuel delivery issue on the starboard engine. It runs fine and then just runs out of fuel and shuts down. Then it will fire back up after sitting for 5 minutes and run for a while and do it again. If I troll on it it's fine all day long. If I pump the primer ball a few times it starts right back up so we know for a fact it's fuel delivery. While it's running it runs perfectly fine so I am pretty sure it's not a carb. problem.

Anyhow, the boat has Chevy 250 6 cyl engines and they are so simple I'm just gonna replace everything on that motor's fuel system and be done with it. Both engines have primer balls....should I keep them or eliminate them? Someone just told me I don't need primer balls on an I/O and that does make sense to me. What do you think?

Thanks!!

[LongLine]

Sounds like either the check valve in the bulb is acting up or a fuel pump has gone bad. You may want to look at or ask on Iboats.com. They have a lot of info on fuel systems.

Tom B.

(LongLine)

[GAMBLER]

Rod,

First check for an area that could be sucking air. I had a loose fitting and it had the same symptoms. Sometimes the fuel lines harden with age and can start to suck air over time at fittings.

[Splitshot115]

Rod,

Get rid of the bulbs, a properly working fuel pump would be able to prime the hose and keep the fuel line filled without the help of the bulbs. Just another connection that can suck air and part to fail.

Splitshot115

[borderline 350]

DEar FT,

It sure sounds like you have a small air leak in the intake line coming from the tank to the pump. I HAVE NEVER SEEN a primer bulb installed on any OEM Mercruiser 6 cylinder Inboard or I/O. Remove the primer bulb and replace the line with 3/8 inch ID marine rated fuel hose. Be sure and pull the fuel supply elbow out of the Searay tank and check the pickup pipe for obstructions CAREFULLY! I have seen the plastic push on pick up pipes cause some frustraing fuel supply problems. Replace with an aluminum pick up pipe with a 45 angle on the end for maximum reliability. I have seen partial blockages in the pickup pipe which a new $100 dollar fuel pump couldn't beat! If there is a check valve fitting in the elbow on top of the fuel tank, BE sure there is no crud stuck on the check ball! Another source of inadequate fuel flow. I have installed 90 degree turn type shutoff valves instead of check valves. You must have a check valve or shutoff valve to meet USCG tankage requirements.

Respectfully submitted,

Jet Boat Bill

[Fishtails]

Thanks guys! The bulbs have been there since I got the boat so I just never gave it a thought till now. I will get rid of them and I ordered new ethanol resistant fuel lines. I do have fuel shut off valves on both motors Bill. I'll be sure to check the pick up while I'm at it to and clean or replace as needed.

[Big Dave]

Clean or replace the fuelfilter too!

[Fishtails]

Quick update...I found the problem. The boat owner (that being me ) Is an idiot....that's the problem. It seems that while doing other routine maintanence, I pinched the fuel line under the floorboard when I put it back on....causing the restriction. I'm so stupid sometimes.... Well, at least there was nothing wrong and the boat gets some new parts

Thanks for the help.

[LongLine]

Don't feel stupid Rod. I just thought a kiwi was a fruit. Glad it wasn't a serious issue.

Tom B.

(LongLine)

[seasquirrel]

Good news!!!!