Motor staving for fuel

[panel350]

Hi All ,I'm new to this forum so here goes.I live in NewZealand and it's summer and time for fishing!! the motor we have is a classic 50hp 4cylinder 2 stroke ,of late she has been running funky gets up on the plane at full throttle then it drops back,if I take the throttle back for about a minute then give full againe off she goes then power drops back again.Being a DIY dude I took off the fuel pump to check the diaphram in the pump as the photos show they are limp ,Is that the cause of my fuel problem???
Cheers
Kev

 

[racerone]

Re: Motor staving for fuel

That diaphragm will work OK.----Filter checked ?---Tank vent checked ?--Look for air leaks on fuel lines / blockage on tank / issues with pick-up tube inside tank.----Possibly water in fuel , but you likely have checked for that.

 

[BatDaddy1887]

Re: Motor staving for fuel

Also.....replace fuel filter(s), it may also be time for new fuel lines, suggest 3/8ths, new fuel pump kit is only a few bucks and may be the culprit anyways. I hope they sell Seafoam or Quickleen in your country to add to the fuel as these products work wonders for keeping the fuel delivery systems quite clean. I would also suggest to connect a small 6 gallon fuel tank with it's own hose to the engine and do some running tests, just to narrow down the problem a bit.

 

[CharlieB]

Re: Motor staving for fuel

Floppy is good, a pinhole or if it becomes brittle and doesn't flex well enough it will reduce pumping.

Most likely you have an air leak allowing the pump to suck air instead of enough fuel.

A simple test is install a piece of clear hose between the fuel pump and carbs. Run the motor and watch the air bubbles passing thru, proving the leak.

Quick disconnect fittings have a habit of failing, the O-ring ages, it seals when pressurized by the primer, yet allows air to suck in under vacuum of the fuel pump.

Check every fitting, clamp, and hoses for cracks, looseness, etc.

Remember to remove that clear hose once finished, it is NOT recommended for fuel, only as a short term testing tool.

 

[panel350]

Re: Motor staving for fuel

Many thanks mates ,new hose problem sorted!!! hasn't run so good!!!!
Cheers Kev
Ps no fish for dinner !!:blue::blue:

 

[BatDaddy1887]

Re: Motor staving for fuel

...get a bigger fishing rod...!!! :lol:

 

[panel350]

Re: Motor staving for fuel

Haha this is what we usually get !!

 

[CharlieB]

Re: Motor staving for fuel

NICE fish!!!!

Someone's happy, and I don't think it's the fish.

 

[BatDaddy1887]

Re: Motor staving for fuel

Wowzy-Wow...!! I guess your rod works pretty well after all...!!!