Fuel Restriction?

[Jason Edwards]

Took the boat out to the lake this weekend with the new prop and high volume screens installed and this is what happened.

The prop worked amazingly well. Holeshot was awesome. All of my gear either slid or rolled to the back of the boat by the time the boat got on plane. The boat almost instantly seemed to get on plane. No loss of top speed was noticed and rpm increased to 5600 rpm from the previous 5000 I was getting with the raker 20P.

But I still have the problem with the check engine light and buzzer going on. It only happens when at WOT and max rpms. I initially thought that my motor was overheating and that was the reason for me installing the high volume water screens. I have been told that this alarm could also be due to a fuel restriction. I had my wife along with me for this trip (bless her soul), so we tried something to test this theory. She sat at the back of the boat and pumped the squeeze ball while we were traveling at WOT. The alarm never sounded until she said she couldn't pump the ball anymore because it practically went flat. When the ball wouldn't "rebound" or "inflate" anymore because the engine was comsuming so much fuel the engine alarm would go off every time.

Where would you start with this problem? I know the problem may be due a faulty anti-siphon valve but is there anything else that might be worth checking first? My fuel tank is a motherbear to get to and any suggestions would be greatly appreciated.

 

[Walker]

Re: Fuel Restriction?

You're gonna have to refresh us a little. What motor are we talking about and what history. This is why we always say to stick to the roiginal thread so we can follow along with the suggestions and symptoms.

 

[rickdb1boat]

Re: Fuel Restriction?

Do you have any other filters inline between the tank and the engine? If the bulb is going flat, that indicates a restriction between the bulb and the tank...Make sure your vent is completely open and the anti-syphon valve is not restricting flow...

 

[mikesea]

Re: Fuel Restriction?

Do you meanyou cant get at the pick up tube at the tank,I have found problems there especially if someone used a brass nipple for a fuel barb,brass and alum.dont get along,the tank vent,bugs often get in there ,right up to the hose,you can remove the fuel fill cover to test and see if the tank isn't venting,how about water seperator,do you have one,check the fuel passages there too,same deal as the tank,ive seen these passages get crap in them,I assume you have a 6 cyl. is your fuel line in good shape,ive seen them collapse inward,like plaque in an artery,the double wall gets delaminated,kinks,you probably have something that is kinda minor,or it would be troublesome moreoften than wot,hose should be 3/8,you can run smaller and get away with it ,but not with bends and twists

 

[Jason Edwards]

Re: Fuel Restriction?

Sorry. I'm running a 200 HP Johnson Oceanrunner hooked up to a 23' Center Console Promaster. This thread was initially posted in the prop section but turned into a mechanical question instead of a prop discussion. The motor has less than 30 hours on it and is a '98 model. I have replaced the fuel filter on the engine side of the primer bulb and have not noticed any other fuel filters than that. My fuel tank is a 60 gallon fuel tank and requires removing the floor and center console along with 3 batteries, bait tank, etc, etc. I can lift up on the floor enough to tell that the pickup tube and sender are directly below the center console, nearly 4 feet further than what I can reach without removing the floor. If it has to be taken out I will have the shop do it. I just want to make sure it isn't something silly before I give up a pay a mechanic $65/hour to fiqure it out.

 

[Jason Edwards]

Re: Fuel Restriction?

Ok, found the fuel vent last night finally and discovered that it is actually built into the fuel cap. Somehow it vents through 3 holes on the underneath side of the fuel cap. I don't see how any air could pass through those vent holes with the cap screwed down tightly. Going back to the lake again this weekend so we will see. If you have any other suggestions please let me know. I'm wanting to rule out everything else before I decide to knock out my anti-siphon valve.

What about the primer bulb? Have there ever been instances of fuel restriction due to a faulty primer bulb?

 

[mikesea]

Re: Fuel Restriction?

yes,the ball could be a problem.try removing the fill cap compleltly if possible to rule that suspect in or out,you can change the ball if you believe its old or when you operate it ,it acts up,if your fuel water seperator is before the ball,be sure all the connections arent sucking air,or that thenipples that the hose connects to isnt full of crap,it does happen when the brass nipples and alumium filter housing have a reaction,look at the hose well, be sure it doesn't have any swellings,kinda like when a garden hose blows out

 

[R.Johnson]

Re: Fuel Restriction?

Put a vacuam guage in the fuel line. if it reads over 3-4 inch's you have a fuel restriction.

 

[rickdb1boat]

Re: Fuel Restriction?

When you change the bulb, make sure to get an OMC one and not a Walmart cheapie. Big difference in them. Also, if you do have a fuel/water separator, try bypassing it temporarily and see how she does...