1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

[didlysquat]

I have recently bought this motor my first ever outboard. It runs great but when I open it up it starves for fuel. It has two lines from tank to carb. One fuel one air. It has a little black button on tank which I assume is to prime. I also assume that tank is pressurized. Does air need to be entering the tank and if so where. The main fill port has a big black cap and there is hole drilled in it where it threads down. Should this cap be tite or loose?

I have been slow in getting back. I took advice and adjusted the high speed control knob. It seemed to make little difference. I took hi speed needle out and it seems worn and blunted. Now the motor smokes more and has no power like it's flooding. Time for a new CARB? and where would I find one?

 

[wbeaton]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

I have recently bought this motor my first ever outboard. It runs great but when I open it up it starves for fuel. It has two lines from tank to carb. One fuel one air. It has a little black button on tank which I assume is to prime. I also assume that tank is pressurized. Does air need to be entering the tank and if so where. The main fill port has a big black cap and there is hole drilled in it where it threads down. Should this cap be tite or loose?

Your motor uses a pressure tank. Since the motor has no fuel pump it uses a pulse of air from the crankcase to pressurize the tank, which in turn pushes fuel out of the tank and into the carb. In order to maintain pressure int he tank the cap needs to be tight. The hole in the cap allows pressure to escape when it gets too high.

The black button pressure tank I believe came out in 1958. What is the model number of your Fleetwin?

 

[R.Johnson]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

The hole in the cap is to bleed of pressure without removing the cap. It is not a pressure relief, that is in the black tank cover. The relief hole is just to the side of the hose connectors.

 

[lindy46]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

It runs great but when I open it up it starves for fuel. (

What does it do? Bog down? Could just need a carb adjustment. Try adjusting the bottom high speed knob when running full speed. If that doesn't work, carb needs cleaning and a re-build kit.
If it feels like it's cutting out, it may be an ignition problem. Probably a bad coil and one cylinder is not firing.

 

[didlysquat]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

Thanks for the response's. The motor model is 7520. The tank is not the original tank it is off a Johnson (6 galllon). Motor runs great at idle I can run around the lake all day without a problem at trolling speed. When you open it up to gain faster speed to come back to home, it starts to to act like it is starving for fuel. I tried pumping the little black button and it keeps going but only for a short ways and powers down like it ain't getting enough fuel. One pull and she is on her way again for about 100 yds. and same event over unless I idle down to trolling speed. It had a new coil put on this spring.

It's not cutting out just powers down. I'll try adjusting the speed control next time out.

Brad

 

[wbeaton]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

7520 is a 1956.

Since you had the coil replaced I assume you took it to a shop and they did the work. So I will further assume the other coil is still good and not cracked, sweaty or discoloured. Try setting your high speed jet next time you are in the boat. The procedure for setting the carb is described in the FAQ's.

Is your tank holding pressure? Also, the little metal filter in the bowl under the carb may be partially blocked and causing your problem. Do some tesing and let us know what you find.

 

[didlysquat]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

7520 is a 1956.

Since you had the coil replaced I assume you took it to a shop and they did the work. So I will further assume the other coil is still good and not cracked, sweaty or discoloured. Try setting your high speed jet next time you are in the boat. The procedure for setting the carb is described in the FAQ's.

Is your tank holding pressure? Also, the little metal filter in the bowl under the carb may be partially blocked and causing your problem. Do some tesing and let us know what you find.

Will do and thanks again!
Brad

 

[didlysquat]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

I'm not quite sure how to navigate around this forum yet. At any rate I tried adjusting the high speed and it seemed intermittent sometimes speed would increase only to drop back and stalling issue arose again.

I took motor off and put in drum. Cleaned metal filter in glass bowl. Cleaned plugs they were wet and oily! Took high speed adustment needle out to examine. It seems worn and blunted. Put all back. Tried in drum. Motor sped up and down without stalling out after 1/2 hour run time. Put back on boat and the high speed idle would not respond regardless of where it was set.

Motor smokes worse than before and seems like it is flooding not starving as previous. Would go all day i think on troll speed but the smoke would kill ya. FYI I am mixing fuel as per manual 1/2 pint per gallon or 40/1. Is a new carb in order and if so where would I get one?

 

[wilde1j]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

How about tank pressure? When you open the cap, there should be a large "whoosh".

 

[samo_ott]

Re: 1956 Evinrude Fleetwin 7.5 fuel tank pressure issue

The fuel mix should be 24:1 of tcw-3 oil. You should try rebuilding the carb first. something could be plugging the high speed circuit. A blunt needle could be an issue though. It needs to be sharp to work. Can you post a picture of the needle?