Evinrude…primer .. not a choke! WEIRD

[omcbeaulieu86]

So I have a 35HP Evinrude.. mid 80’s and it doesn’t have a choke. Instead… 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… 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. 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.. im not sure.

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!

[frankr]

Not as weird as you think. OMC changed to the primer system on a ton of motors about that time. Including on my 35hp (electric start). And no, there is nothing in front of the carburetor either. The hose you are speaking of is the crankcase drain hose. Goes to the upper bypass cover to inject the drainage into the upper cylinder for burning. Not sure what the deal is with yours.

[billw]

If the engine were mine, I would, without a doubt, start by cleaning out the carburetor, if it has not already been done. The main, high speed jet sits right on the bottom, where all the potential crud collects.

Once you learn how to start a primer motor, you can most times start them with one pull, even in the dead of winter. I like them, myself…..

Long live American manufacturing!

[omcbeaulieu86]

Very interesting ! I will have to take that carb apart again. It looked very clean and I tried to take that long piece of brass out but it started to break so I left it alone. Perhaps it is gross below. Right now the crank case drainage gets cycled back to the top of the carb where the primer shot gets introduced into the carb. I may have found the place where the drainage is suppose to go, behind the fuel pump.

Thanks for the tips. I hope it makes a difference.

[frankr]

The high speed jet is deep in the hole, behind the hex plug in the very bottom of the float bowl. It probably has crud in it. You are supposed to use a special screwdriver to remove it, but you can leave it in and soak the whole bowl in carb cleaner.

[fleetwin]

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.

[1946zephyr]

Yea, it sounds like the main jet is partially plugged. Probably from old dried fuel mix and dirt.

[dan-in-tn]

Don, didn’t they have a half way point for the primer also just to add to the confusion for warm up? After start up you pushed the primer part way in and some fuel continued to bypass the primer till the engine was ready to run and then you had to push it all the way in which was full off! You had to be a mechanic to tell what the engine wanted, but if you were it was a neat feature. You remember " Featureless benefits and Benefitless features! Think about that one for a minute.

Dan in TN

[fleetwin]

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".

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