OK to run outboard 1 cylinder not working ?

[Jetav8r]

OK, here's a good one.

Have a BF50 4-storke Honda on a sailboat and bottom carb is not working. If I spray gumout into it motor runs perfect. Have removed and cleaned carb but no effect. May be low speed jet "tube" which is no longer available and notorious for clogging.

While I source this part, fix, or find a whole new carb........... QUESTION:

Motor is pretty useable on 2 of 3 cylinders from idle to 3,000 rpm.

Is there any reason I should not use it this way till end of season?

Only use this to get in/out of slip.

Appreciate opinions. Cheers.

 

[Scott Danforth]

I wouldn't

 

[ahicks]

Check out #19 here, status is showing in stock:

Honda Outboard 50HP OEM Parts Diagram for CARBURETOR | Boats.net

Buy OEM Parts for Honda Outboard 50HP CARBURETOR Diagram

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I would clean it, have done a BUNCH of these. Likely the #1 issue with the 40 to 90 hp Honda's I work on.

There's a really tiny jet located in the bore of this part. When you THINK you have it clean, you should be able to see through it lengthwise. If you can't, it's not clean!! Hole not much bigger than a whisker, so trying to clean it with a piece of wire that's too big can damage it. If you have access to a small wire brush used for cleaning small parts (the ones they sell for a dollar or so), you can use a pair of pliers to pull ONE bristle, straighten it, and use that to clear it.

I might run one long enough on 2 cylinders to limp in, but finishing the season out like that probably not a good plan. Just trying to get in gear without stalling is going to be a trick, may result in damage to the bottom end.

 

[jimmbo]

If the engine is not firing on all Cylinders, it is not producing all it power, which means the remaining Cylinders will be overloaded and will not attain the proper WOT RPM, which is usually a Death Knell for most engines

 

[Jetav8r]

Guys, thanks for feedback !!

Yes, thanks AHICKS. I can source the low speed jet tube. Honda's site confusing there.

Will again clean carb and replace tube. Probably solve issue.

As for running with a cylinder down.... the engine actually runs fairly well at idle and can easily shift into fwd / rev. At 2-3000 rpm it also runs fairly smoothly but cannot get over 3K it bogs down and dies.

To move boat in / out of slip is like 2000 rpm and half throttle. Not asking much of the engine at all.

I should mention several ideas here about running with a cylinder out as a beer debate discussion I have already had with other gearhead friends:

- Would be bad idea for 2-stroke as you maybe would not be getting oil in the cylinder correctly ?

- some older motors (example Mercury 115) actually shut down a cylinder below ? some RPM to conserve gas. So, I don't think this is an issue.

- Tuliped a valve in an older 5.7 Vortec V8 Merc years ago and ran the boat the entire season with a cylinder down. The only way you knew something was wrong was it would knock above 3500 rpm (dieseling).

- Would be bad idea for IO motors today because they have cat convertors on them and unburned fuel would be a melt down.

I know...... crazy talk.

 

[ahicks]

I thought you said the tube was no longer available?
"May be low speed jet "tube" which is no longer available and notorious for clogging."

Beer talk, I get what you are saying. The 2 strokes would be out of the question. On a 4 stroke though, the cylinder that's down is still lubed normally.

 

[MattFL]

Bogging down and stalling is an entirely different problem. I had to run my 50 on two cylinders for a while when the float valve on one clogged up out in the ocean and I know what you mean that it doesn't seem to object, just down on power. If you keep in mind the other 2 cylinders are working extra hard and don't push it then it's unlikely to cause major damage, but I would not consider it reliable until the bogging/stalling problem is sorted, that might be more likely to leave you strand. Side note, if you can get that tube out, sometimes heating it lightly with a flame can boil out the black goo, just do it far from any gas and don't get carried away with the heat.