Fuel Delivery Speedster

[Jnz]

I have a fuel delivery issue on my 98 speedster twin 787s. On the right engine everything runs fun starts right up and fuel filter is full. The left engine does not start right up and does not fill the fuel filter and seems to use the the fuel then die. I was chasing the issue and tested the diaphragms in the fuel pumps and the could not hold any pressure. So I replaced both fuel pumps with the high flow mikuni pentagon pumps and routed each outlet to each inlet on the carbs. Got some advice from a local power sport mechanic and he suggested switching the input line from the engine that fires right up to the problem engine and vice versa. The problem engine fired right up and got fuel In the filter and the problem went to the other engine. Now I know the problem has to come from either either the pickup leading to the fuel pump Inlet. Pulled the lines and plugged one end of each and it's sealed no cracks. I am using Fram g2 filters and can't see anything wrong with those. I pulled the baffle, but don't don't know what could be wrong given it pulls fuel for one side just fine. Any suggestions ?

 

[Danosll]

Did you check your fuel selector valve? Could be obstructed with debris

 

[racerxxx]

I forget the connections on the speedster, but I vaguely remember posting info about it. But I'm almost 100% certain that each engine had its own port on the fuel baffle, are you on the correct ones, not on the vent line? Did you swap the line at the pump or the baffle? Anyway, you need to determine if the line is the problem, the baffle is the problem or the line is on the wrong port on the baffle or the filter is the problem.

How much gas is in the tank?

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[Jnz]

Well I didn't replace the lines originally to the baffle they still had the factory clamps on them and all were going to the right spots and your right on its own port instead of a selector and reserve it just feeds each input at the fuel pump. With the new fuel pump everything is plumbed right. Since its apart now I will just replace the two feed the lines off the baffle completely and even though these are two brand new filters replace those as well. Trouble is I've never had a problem with the g2 filters and once before I remember using a puralator filter from the auto store. I remember when you looked the puralator filter it is cross referenced the g2 as a replacement. The tank is full.

 

[racerxxx]

I remember this boat came as "some assembly required", were the fuel lines open? A bee or bug could have made a home in the open tube. What I would do is that the engine that you know runs and use that supply line to the engine that doesn't run. But just the part to the filter. Use the filter and line from the non running engine and see if it runs. Then try the other engine and see if that one doesn't run. It'd process of elimination.

Danosll, as far as the fuel selector goes these boats do not have them.

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[Jnz]

Trouble is yesterday when I took it apart I separated the hoses and filters and don't know which one caused the trouble. Haven't got a chance to mess with it today yet, but bought some new fuel hose and might just pick up two new filters even though these two are new also. The baffle doesn't appear to have anything that can cause fuel not to come up only one inlet. The adapter at the bottom which must be only used in boats does that come apart ?

 

[USAF_Pride]

I forget the connections on the speedster, but I vaguely remember posting info about it. But I'm almost 100% certain that each engine had its own port on the fuel baffle, are you on the correct ones, not on the vent line? Did you swap the line at the pump or the baffle? Anyway, you need to determine if the line is the problem, the baffle is the problem or the line is on the wrong port on the baffle or the filter is the problem.

How much gas is in the tank?

Sent from my SGH-T889 using Tapatalk

Correct. The fuel lines connect to the normal connection and reserve (there is no reserve in the boat). The return is connected with a T and the vent is just that. Make sure the return is connected properly.

I have the same boat and I have neither a fuel selector or external fuel filters.

 

[Rpd183]

I have same boat same problem. Nobody ever finishes these posts and says what was wrong or how they fixed problem. It's now 2015 please respond as I have same problem. Thanks

 

[Jnz]

If you follow my threads you'll see that i actually chased this problem until about a week ago. My problem ended up being one of the plastic valves in one of the new fuel pumps came cracked. Since it was new i never went back to that and therefore kept chasing problems that weren't there.

 

[Jnz]

If your situation is truly like mine and you have one good running engine it will become easy to diagnose. I started with fresh gas, oil, and plugs. Then You can swap input lines to the fuel pumps to determine a problem in that line or pickup. You can also swap carbs over and fuel pumps. Just be sure to do one thing at a time and test. The time you try to do multiple will burn you.

 

[Rpd183]

Thanks for the response. I tracked down the problem to the fuel pump and a new one is on order. Thanks for the help.

 

[Jnz]

You bet. Glad you found your problem.