Evinrude Manual Fuel Pump
So I have a 35HP Evinrude. Mid 80's and it doesn't have a choke.
It has a pump primer to directly spray fuel into the carb near the reed valve plate. It bypasses the butterfly valve.
I took this out on the water for the first test today and it started and idled beautifully! I set the low speed to 1 1/4 and it couldn't have idled any better. The choke is non existent so when I look down the carb I see just the butterfly valve which is moved by the throttle. When I try and speed up.
The motor wants to quit and just die right out. When I put two fingers over the hole where the choke normally is.
Chevy Manual Fuel Pump
It runs a bit better and I can really feel the suction. I wonder if the engine is getting too much air since the cowel is off and there is nothing blocking the outside air rushing in. I put the cowel on but no change. It bogs down right away. There is a small nipple where a tube is attached to it on the reed face plate below the carb on the left.
Evinrude Fuel Pump Diagram
Evinrude Fuel Pump Test
On my buddies evinrude 35, which is similar, this tube runs back near the fuel pump (just behind the fuel pump but not hooked directly to the fuel pump) I assume this is to send pressure. Or even out pressure.
Well on MY motor. Which is similar. I dont see a place for this to hook up to. I took some pics, and I can email someone who is interested in looking at them. I've never seen a primer on an outboard like this before. I would love an opinion on what might be bogging down the motor and what that nipple on the reed face plate is for.
Thanks experts! I will send out pics to anyone who puts their email down. I want to get this puppy running before the snow hits! OK, well I agree, the manual primer is confusing and tough to work.
A conventional choke must be cheaper to produce than all that CPS crap. Once I figured them out, I agree, I could use the primers and they worked pretty well. But, customers don't figure them out, and they cause needless frustration and dissatisfaction with new engines. But, more to the point on your symptoms. The late 80s 25-35hp engines were known for being lean off idle, in other words, they loved to spit/fart/stall when run at speeds about 1500 RPM in gear.
OMC did publish a bulletin recommending retarding the pick up timing slightly to richen up the mixture a bit off idle. In other words, have the carb butterfly start to open about 3/4' past the notch/line on the throttle cam. This is a simple solution that usually works out well for these cold blooded engines. I remember CPS, CRS, and Casey's great comment about.' If an electron flows through it, OMC can!@#$ it up!'
How about 'voo-doo ignition', that was fun too. Yeah, that manual primer had a 'warm up position' that just added a little extra fuel during warm up to combat the engines cold blooded tendencies. How much time was wasted diagnosing a poor/no idling condition that was caused by the owner leaving the manual primer knob in the warm up position? The plastic knob had a squishy/weak feel, you had to know the difference between just pumping air (after a customer let motor run dry) and when the knob was actually doing something when you pulled it all the way out and let it release back. And how about the lovely plastic fuel bowls on the cross V models that made shavings every time a jet was removed/installed, the warped mating surfaces were great for fuel leaks too!
I remember Billy C's solution for the sticky solenoids: 'tap on it'! We laugh now, but it was really very sad stuff, a direct result of bean counters 'running the show'.