1989 Evinrude 75 HP - Running on One Cylinder? (Videos Included)

[seasquirt]

Most carbs have the float level needle and seat we all know, and also the long main jet needle attached to the slide or diaphragm, which opens closes many small holes in the sides of the brass tube; and then also the bleed needle adjustment at the side for either fuel or air depending on where it is - cylinder side or atmosphere side, as I mentioned above - which can be bottomed out. Also the low speed jet which has no needle but can get blocked anyway. Clean them all.
If all the bleed needles were closed off then someone had set them up wrong most likely. Often they are very pointy brass, with a tiny O ring near the point, then a tiny metal washer, then a tiny spring butting to the thread, and another small O ring closer to the outside near the adjusting slot, to stop fuel leaking out. If the O rings were damaged / missing and leaking fuel someone may have closed them off. Find an exploded view diagram, and maybe 3 carby kits containing all new brass and O rings and washers and seals. Keep the old bits as backups. You'll be an expert soon.

 

[OnThePontoon89]

I may be incorrect here, I may in fact have a 1982. This looks far more like my carb. I googled the carb part number and 81-82 kept coming up

https://www.marineengine.com/parts/...RCNB&manufacturer=Evinrude&section=CARBURETOR

The screws bottomed out are 26, 37, and 3. Nothing here looks adjustable at all

 

[OnThePontoon89]

@fallguy

Confirmed this is a 1982 E70ELCNB, that's what we're working on . I edited the main thread. If an admin can edit the title in case someone searches this down the road.

My cowel stated 75 HP and a friend stated 89 so that's what I was going on.... Finally found the part number on teh freeze plug and gave the folks at marineengine.com a call

 

[fallguy]

Make sure all orifices are clear. I don’t see a main needle; not sure. 11 and 33 and any other orifices.

Pay close attention to differences between the function one and the other two. Sorry, I don’t know that carb at all.

 

[SolGato]

I may be incorrect here, I may in fact have a 1982. This looks far more like my carb. I googled the carb part number and 81-82 kept coming up

https://www.marineengine.com/parts/...RCNB&manufacturer=Evinrude&section=CARBURETOR

The screws bottomed out are 26, 37, and 3. Nothing here looks adjustable at all

You’ve done some good troubleshooting thus far.

According to that diagram, the parts behind those screws (27, 35 and 33) are what do the metering. That means the screws should be bottomed out.

Remove those parts (jets) and make sure they are clear, then make sure you have a good O-ring (36) and fiber washed (1) behind those screws that seal off the passageways.

Your carbs appear to use an air bleed system to meter A/F at idle and cruise in conjunction with progression holes in the carb throat.

High speed is then metered and fed by the well in the center of the bowl with fuel drawn up the brass emulsion tube (should have little holes in it).

For idle and cruise metering, in addition to the “jets” being free and clear, you also need to make sure the small progression holes are clear in the throat along with the passageways to the air bleed.

And then for the high speed circuit, make sure the passageway behind the screw plug in the bowl is clear as well as the emulsion tube.

Then make sure your needle and seat are clean and the bowls are filling, and set your floats appropriately.

Once you get them working, make sure you sync them.

You didn’t by chance have any timing work done to it?

And is the water oily or is it fuel? If you had x2 cylinders not firing but sucking in raw fuel, it would be blown out the exhaust. However you stated you felt the plugs showed no signs of fuel?

Strange, because clearly there is fuel running out of the carbs. The spitting however makes me suspect a timing issue.

If sorting the carbs out doesn’t do the trick. I would be going over and verifying the timing.

Lastly I wouldn’t bother swapping carbs. The center should be your lead and likely has different parts and features than the top and bottom.

 

[OnThePontoon89]

So here's where I am guys.... Cleaned and dipped the top and bottom carb. Not sure if it's due to increased idle but the top cylinder *can* hold it's own (still not as good as the middle). Bottom will not hold it's own. When I say hold it's own I mean run only on one cylinder. I am still getting the spitting so I removed the manifold to expose the reeds. These seem to look bad. The middle obviously looks best but there is still a little hole. Will you ever get these to seal 100% perfect so there's no light at all? Here's some videos

https://youtube.com/shorts/T0QPG5R_NVY
https://youtube.com/shorts/i6Y1SD_J3JE

I'm going to replace. Any advice on the part number for JUST the reeds and not the whole assembly. I found some on ebay not sure how good the carbon fiber ones or I should stick w\ OEM. are Reed Valves 1982 Evinrude for sale | eBay https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4432023.m570.l1313&_nkw=reed+valves+1982+evinrude&_sacat=0