Ok Evinrude gurus qustion for you

[V1 Rotate]

Finally am getting around to rebuilding the carbs and am glad I did. I found a couple things that definetly needed taking care of. One thing I found was that the small drain hole at the bottom of the air box was completely clogged and the damage can be seen. I am curious though as to where that drain goes. It appears to go into the engine block but where from there?

Next the screw on one of the carbs that covers the jet that sits at the highest position on the carb was completely loose. This to me would let it suck air instead of gas. Which jet is that and what do you think it being loose would do to running of the engine? It was cutting out and I am wondering if this would cause that. In the first pic you can see the screw flush with the carb body and in the second you can see the damage done by not having the drain clear.

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

That drain hole in the air box is just to clear out gunk that falls into the bottom and drain any overflow gas out. Normally, it does nothing at all. But if it does, it just drains out into the outer cases.

The loose low-speed jet adjuster indicates worn packing. You'll get new packing in your rebuild kit. And yes, totally loose and it will suck air like you describe. Rebuild, clean, and use all new washers and packing and you'll be right as rain.

Edit: Looking at the picture, I can't see any packing around that adjuster at all.

 

[jtexas]

Re: Ok Evinrude gurus qustion for you

I have been told that the drain in the airbox is there to collect excess oil and deliver it to the lower crankshaft bearing for supplemental lubrication - but I have no proof of that.

that's gotta be a pre-1981 motor, I'm guessing pre-'76; the idle jet is fixed - that's no adjuster, just a screw plug. I'm thinking - it'll lean out that cylinder, and be more noticeable at higher speeds.

 

[WillyBWright]

Re: Ok Evinrude gurus qustion for you

Interesting cable anchoring going on there.

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

I have been told that the drain in the airbox is there to collect excess oil and deliver it to the lower crankshaft bearing for supplemental lubrication - but I have no proof of that.

If you look, you can see it just scavenges into the tube and drains out into the outer cases.

Loose drain plug will do the same thing - suck air. But, does the plug have the fitting for the packing (the notch)? Maybe - kinda odd though.

 

[jtexas]

Re: Ok Evinrude gurus qustion for you

good, I can stop being so vigilant about keeping it connected, that dang hose is hard enough to connect and half the time it slips off before you're done................

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

I think if the lower bearings required scavenged airbox gunk to keep lubed . . . well I'd call that a design flaw for sure.

:0

 

[F_R]

Re: Ok Evinrude gurus qustion for you

The silencer drain hose is there because there will always be a bit of blowback and leakage from the carburetors. The drain hose is supposed to be connected by a hose to a nipple in the intake manifold, below the bottom carburetor. It is not supposed to drain into the cowling or lake. From the intake manifold it is merely drawn into the fuel/air stream to be burned in the cylinders. That sure is a cruddy silencer--what is all the crap in there? Looks like even some water (rusty choke plate). I hope the water didn't get on into the reeds and crankcase.

Now for the screw: Once upon a time, they had adjustable idle mixture needles in those holes with a plastic friction ring around them. The notch is for a tang that was on the friction ring. However, these carbs have fixed idle jets instead of adjustable needles. So the old needle holes are merely plugged with screws with gasket washers under the heads. They are supposed to be screwed in tight to prevent sucking air around them. The notch is still there because they continued to use the same castings as were used with adjustable needles.

Hope this clears it all up.

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

Thanks for the clarifications, F_R.

 

[jtexas]

Re: Ok Evinrude gurus qustion for you

shoulda waited for the *real* guru

I dunno, iwombat, the oil collected on my airbox is pretty clean, I believe it'd lubricate ok.

you thinking V1's motor was submerged? you didn't by any chance buy it somewhere along the Mississippi Gulf coast, did ya V1?

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

Remember though, you're collecting anything that happens to get sucked into the airbox too. Little bits of insulating foam, dust, grease, stray monkeys, and the occasional stunned gnat. Probably all fine to pass through to the combustion chamber, but not fine to count on as a key source of lubricant.

Especially those stray monkeys.

I really appreciate F_R's info though. I don't think I've ever come across one that was hooked up properly. If I did, I just didn't notice. Now I'll start looking.

 

[V1 Rotate]

Re: Ok Evinrude gurus qustion for you

yes the gunk is there in the carb and airbox from the clogged drain. It did rust the choke plate but not too bad that I can not fix it. The carb is actually clean on the other side and the reeds looked great. I know the jets are fixed I just didn't know which jet the top one is. The screw there is fixed and I know that and it just lets you put the jet in there and then seals it. I just was wondering if it leaked which I am sure it did what effect would leaning that jet have since I didn't know what jet it was for.

Kits are on the way to rebuild the carbs and they are soaking in seafoam and gas until the kits arrive.

I hope that my pics will show everyone that a little time removing the airbox might save them some trouble later on. Get in there and check it!

Thanks everyone for your comments!

 

[jtexas]

Re: Ok Evinrude gurus qustion for you

That little hole just to the left of the idle orfice - does air get drawn in there at idle, or is it just when the choke is closed? or all the time? And how much does that circuit contribute at higher speeds? if any?

I can't tell from the pics - do these carbs also have the off-idle circuit?

 

[iwombat]

Re: Ok Evinrude gurus qustion for you

Belated thanks for the stinger there, JTexas.

I'm an admittedly experienced hack, not an expert. Sometimes I just need reminding

 

[F_R]

Re: Ok Evinrude gurus qustion for you

jtexas, if I remember correctly, that hole to the left is the bowl vent. I'd have to verify that with a looksee.

 

[jtexas]

Re: Ok Evinrude gurus qustion for you

bowl vent......I'd of sworn the passage connecting that hole to the roof of the bowl has a core plug in it (on my '79 3-cyl), but anything sprayed into it comes out......somewhere......I convinced myself it was an air circuit of some kind............

[note to iwombat, I was referring to myself as well]