72 inline 6 to much fuel cilinders 3 - 6

[Reinder]

I cleaned the carburators on my 1350 inline 6. It ran fine at first, but now it seems to work only on the top 2 cylinders. When the sparkplugs come out they are black and wet. When I disconnect any of the lower 4 ignition wires from the distributor I hear no difference in running.

Engine is my project-engine. Ran fine when I first put it together then started acting up after about 15 min. on the water. In the short time on the water trying to get it to run it guzzled trough gas.

Should I just look at the floats or are there any other carburator issues that I should know about.

Thanks in advance for any input.

 

[Fuzzytbay]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Did you do a link n sync on the engine after you rebuilt the carbs?
If you didn't that could be part of the problem. Also after the plugs fouled, the first time, did you replace them?

 

[Reinder]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Yes, did the whole sync routine.

No, did not replace plugs after fouling. There is no carbon build up. I have no experience with those surface gap sparkplugs. My last two-cycle was a moped.
Should I replace or can I clean them ?

thanks

 

[sschefer]

Re: 72 inline 6 to much fuel cilinders 3 - 6

I'm not up to snuff on inlines of that era but just from the description I'd have to say you messed up the floats or needles when you installed them. The condition you describe, (guzzling fuel and flooding) would lead me to belive that the float needles are hung open and fuel is flooding through.

 

[Fuzzytbay]

Re: 72 inline 6 to much fuel cilinders 3 - 6

You have to wonder,what you did different on carbs 2 and 3, compared to carb 1. If you did mess up the float level setting, then that could be it. Another thought, did you check for spark on 3-6?

 

[Reinder]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Looks like the floats are sticking on the rod in the center of the bowl.
I used a small drill to give them a little more clearance and they seem to work fine now. Hope the floats are closed cell foam, otherwise I'll be back taking them apart and replacing floats.

Seems I also have different needles in my carburators. Two metal tipped, one rubber tipped. Guess there where more tinkerers before me. I'll replace the seats and needles.

Will keep posting.

thanks to all who replied.

 

[daveswaves]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Looks like the floats are sticking on the rod in the center of the bowl.
I used a small drill to give them a little more clearance and they seem to work fine now. Hope the floats are closed cell foam, otherwise I'll be back taking them apart and replacing floats.

Seems I also have different needles in my carburators. Two metal tipped, one rubber tipped. Guess there where more tinkerers before me. I'll replace the seats and needles.

Will keep posting.

thanks to all who replied.

You would be best to change the floats unless they are the new white plastic style. The orangy brown foam ones are not closed cell, they were coated with a shellac which you probably penetrated when you clearanced the center hole. Needles and seats are a good idea, the old neoprene tip will not be compatible with the alcohol in today's fuel.

 

[Reinder]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Thanks DavesWaves,

new floats it is.

 

[Laddies]

Re: 72 inline 6 to much fuel cilinders 3 - 6

If the problem continues after the floats and you have not replaced the fuel pump diaphragms you will probably find them cracked it's a very common problem when the bottom 4 are flooding.

 

[emckelvy]

Re: 72 inline 6 to much fuel cilinders 3 - 6

You might also consider rebuilding the fuel pumps, as a leaky pump diaphragm can cause excessive fuel consumption.............ed

 

[Reinder]

Re: 72 inline 6 to much fuel cilinders 3 - 6

I put in new diaphrams and all new fuel lines when I first put it all together agian. Clearly the engine had been sitting for many years, I won't bother guessing.

It makes sence that the new Ethanol fuel dissolves the shellac on the floats and that they start sticking. For the top carburator it will be just a matter of time I guess so I will replace that one too.

Again, thanks to all the replies I've gotten I have been able to put this puzzle together. Certainly a lot is due to the gasohol and I'm pretty sure she'll do fine next time on the water. Hopefully there will be a few good days in december to try it.

thanks

 

[Chris1956]

Re: 72 inline 6 to much fuel cilinders 3 - 6

Just so you know, the original inlet needles were ss needles and brass seats with rubber inserts. The replacements are brass seats and neopreme-tipped ss needles. Mixing them doesn't work. Also, the original foam floats tended to disolve after a while. The new hard plastic floats can crack, so keep an eye open for that.