175 Johnson starved of fuel

"hi all -

I have a 1989 1

"hi all -

I have a 1989 175 Johnson.

I have 2 fuel tanks connected to a t-piece switch, then to an electric fuel pump - through a filter to the motor. - All fuel lines and breather lines have been replaced & tanks cleaned.

My Problem is - the motor idles well & goes great at WOT, however when i have been going for 4-5 minutes under load - it powers down to a stop or an idle - starving the motor for fuel. The primer bulb to the respective tank gets sucked in and cannot be primmed.
When tanks are switched - the same happens however, the 1st tank's primer returns to full.

I have checked the filler line filters on both tanks & the main filter and all is clear. I have run with the fuel caps off and this problem still occurs.

Any assistance would be greatly appreciated.

thanks in advance"

"The best is to use simple shu

"The best is to use simple shut off/open valves on the lines from the tank, then connect to a T. Then a single line and bulb, 3/8 all the way, to engine/pump. One valve closed, one open depending on which tank You want to use."

"The flat primer bulb indicate

"The flat primer bulb indicates a severe fuel restriction at some point between the primer bulb and the fuel supply. The usual cauuse is a sticking anti siphon valve BUT that would be quite unusual pertaining to TWO fuel tanks. However, for reference........

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vaccum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"

"In passing along a little mor

"In passing along a little more info,..one of BRP's info's...was not to use aluminum 'cheapo' anti-syphon valves...they are making a brass one.the prob is the steel ball gets stuck,inside the corroding aluminum fitting."

Thanks for your quick reply -

Thanks for your quick reply - I did forget to mention that the electric fuel pump replaced the omc fuel pump- it also has a dial to set the pressue which it pumps fuel.

My rear tank - I took the filter off the feeder - this problem still occured.
i can't tell if I have the anti syphon filter - but the connection is a brass fitting.

I just feel that although it appears that the problem is on the fuel tank end - it maybe the electric pump or something to do with the motor.
Thanks Again

Peter

A small thought about the mate

A small thought about the material: not allways advisable to mix brass fittings on an aluminum tank = Galvanic corrosion!

To narrow the cause...... temp

To narrow the cause...... temporarily rig a fuel line from that electric pump to a portable tank.

"thanks - will try that - [img

"thanks - will try that - "

"hi again and thanks for your

"hi again and thanks for your suggestions - I took it to my mechanic and he seems to think that running two tanks and an alectric fuel pump with a primer on each fuel line is the problem. He says that primers are not required. Any thoughts?

Just one last question - I am running a 4 blade renegade 17" pitch (on the 175HP). When going at say around 25 mile I trim up slightly and pick up 2 -3 miles however, I try to move the throttle to go from 27 - 30, and there is no response. I keep moving the throttle, then all of a sudden I have a sudden burst of speed up to 35mph. Any suggestions - Thanks in advance - Peter"