Replaced fuel line and now bog to idle or stop!

[Swivelhart]

This spring I replaced all the fuel lines under the cowl. I just got the stuff from the local auto parts store. Last fall I had the boat out and it ran great! Took it out for the first time and it took off great and ran at full throttle for about ten seconds then bogged. It would stay idling and then if after 1 min gunned it again it would take off and die again after ten seconds. I had my daighter squeeze the primer bulb while it was bogging but it only made it surge up and down and then come to an idle. The other new thing I did was buy one of those clear in line fuel filters from walmart and placed it just before barb connector on the engine (the tank hose is what im talking about). When it would die I noticed the fuel filter was full of fuel but it would surge if I squeezed the bulb. Consistently though If I let it idle for a minute and then gassed it she would take off full speed for another ten or 20 seconds. My only guess based on what I have done since fall is that the fuel line is kinked. This I know for a fact that the tight turns by the carbs make the line look flattened but I figured enough gas would pass the smallest passage even if kinked. Any thoughts!!!
I dont think they sell the pre formed lines anymore, or do they?

1976 70hp Johnson

 

[EricJRW]

Re: Replaced fuel line and now bog to idle or stop!

Just one more thing to consider: I went about replacing fuel line this past weekend. I started with the larger and then did the smaller. In doing the larger (first) I disturbed the smaller quite a bit. Boat ran worse. Turns out moving those lines around caused the ethanol induced crud (evidence by black specs in fuel going to carbs, AFTER the fuel filter) to get into my carbs. I just finished pulling the bowls and both have crud fouling the orifices (for sure high speed, I suspect intermediate, and I suspect needle valve too).

While kinks are not good, a slightly longer piece of house will help make the bend radius larger and therefore less likely to constrict. Hopefully that's all it is. For me, I'm rebuilding the carburetors.

 

[oldman570]

Re: Replaced fuel line and now bog to idle or stop!

Check online at puregas.org for gas stations near you that sell gas without any ethenoial, or use newer fuel line made to handle ethenoial gas.
Oldman570

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

Has anyone had problems with the bigger lines kinking and creating issues? It sure acted like fuel starvation. The space to work with is very limited under the cowl.

 

[emdsapmgr]

Re: Replaced fuel line and now bog to idle or stop!

A number of the fuel lines under the cowling are special. The factory specially forms these hoses so that they bend sharp corners in a tight space and will still flow appropriate amounts of fuel. If you use bulk fuel hose and try to bend it, likely it will develop a restriction at the bend. The factory hoses that are specially heat-bent all have their own unique part numbers. You may want to consult a factory parts list to determine if you need to replace any of the bulk hoses: epc.brp.com. Keep in mind that the original 1976 fuel hoses on the engine were not made to handle today's ethanol fuels. They can break down over time. Possible to get black bits of fuel hose through the carbs and that they can lodge in the jets-causing a restriction. This goes for the fuel pump bladder also-not likely you still have the original 1976pump...

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

I took a picture of what I believe was the culprit! Tell me what you think. My theory is that the restriction was enough to cut the flow at high speed but enough to allow it to idle without any problem while slowing sucking more gas until I could rev it up and take off for 10 seconds until that bit of fuel ran out. Then it would idle again and repeat the process. My guess the reason it would surge is because when my daught squeezed the bulb it was forcing just enough past the kink to give the engine a boost but not enough to keep it going. What do you think? I will check part numbers on the fuel lines but I also was thinking about getting a couple brass elbows to eliminate the kink spot. Would that work?

 

[EricJRW]

Re: Replaced fuel line and now bog to idle or stop!

That looks pretty bad. Definitely could be a problem.

 

[emdsapmgr]

Re: Replaced fuel line and now bog to idle or stop!

Looks like a good reason for fuel starvation at full throttle. That's exactly the problem with using bulk hose in these situations.

 

[oldman570]

Re: Replaced fuel line and now bog to idle or stop!

A barb elbow should work fine as long as you have a good seal on the hose.
Oldman570

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

Thanks...What about sliding it through two half inch copper elbows to hold its shape. I already tested a left over piece of the same hose by pushing it through one elbow. Its a perfect fit and I would think it would keep its shape using it as a sleeve.

 

[Outsider]

Re: Replaced fuel line and now bog to idle or stop!

Looks to me as if you'd soon have a hole in the line even if you hadn't kinked it. Nothing like professional help ... :redface:

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

I found that a 90degree 1/2 inch copper elbow works as a perfect sleeve for 3/8inch bulk fuel line. Put a little grease in it and then push the line through place it on the tight bends (if it fits) It will keep the line from flattening out. I will test it tonight and report back!

 

[archcycle]

Re: Replaced fuel line and now bog to idle or stop!

That's a brilliant idea let us know how it works. I'd still be concerned that 90* has caused it to kink inside the pipe but just gave it a more attractive presentation though. I had a similar issue recently (though did not run it kinked) and ended up just using a longer segment of hose and routing it a little differently than the stock hose. Building off of your idea it might be better to use a pipe bender to gradually work it around into a smooth 90 turn to solve the kink inside of the elbow issue that is probably going on in there now. Even if it's not kinked having such an abrupt turn may harm fuel pressure. |_ is very different from ( when it comes to moving liquids through a pipe.

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

You might be right! It was a fairly snug fit so I figured it would not allow it to kink but lets see! If it does not work then longer hose will be the solution!

 

[egclassic]

Re: Replaced fuel line and now bog to idle or stop!

A copper 90 is still a very tight turn, hose could still be kinked an you can't see it now. Could you have used a 45 instead?

 

[EricJRW]

Re: Replaced fuel line and now bog to idle or stop!

A copper 90 is still a very tight turn, hose could still be kinked an you can't see it now.

That's what I was thinking... I think I would have gone this route (two required):



And maybe that would allow the hose to be a tad shorter and away from what is maybe is the water jacket.

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

I am taking out tonight to check. My theory is that as a hose flattens it must become wider. The fit is so snug that I would assume (and maybe assume wrong) that it will not allow it to flatten while keeping the passage open. It is a tight turn I agree!

 

[busted-bayliner]

Re: Replaced fuel line and now bog to idle or stop!

Check online at puregas.org for gas stations near you that sell gas without any ethenoial, or use newer fuel line made to handle ethenoial gas.
Oldman570

tried that site didnt get me there u forgot the dash in the middle here the link for
http://pure-gas.org/index.jsp?stateprov=IL

 

[Swivelhart]

Re: Replaced fuel line and now bog to idle or stop!

Well I am happy to say I took the boat out tonight for about an hour and a half and it didn't skip a beat. I can't say it would work with every situation but it fixed my problem perfectly. Never had to pump the bulb from start to finish. Once again it was typical 3/8 inch bulk house from autozone and a half inch copper elbow.