Possibly airbound? (1986 9.9 evinrude)

[Fronterra]

Took the boat to the lake today, engine fired right up and off we went. Got about half a mile down the lake and the engine sputtered out. Could only get it running by fully choking it and then it would run slow and rough. Got back to the dock and started checking the fuel system. Found that the screw holding the fuel filter casing on was only hand tight, and also my fuel hose connection was a little bit loose and not fully seating. I tightened the fuel filter casing and I cut a small o-ring and put it on the fuel side of the quick connect. Got the boat home, hooked up the muffs and started the engine. Engine ran smooth and strong, I did not have to choke it at all. Ran the engine for about 15 minutes on muffs at different speeds and also put it in gear, everything ran great. Engine was recently serviced before I bought it, I have been on the lake about half a dozen times in the last month with no issues. I plan on going back to the lake sunday to run it again under a load. To me it seems like I may have airbound the fuel system? Any other recommendations from ya'll? Thanks in advance.....

 

[Chinewalker]

Re: Possibly airbound? (1986 9.9 evinrude)

These motors can't really get "airbound" as the carb is vented to allow any air to escape. More likely your carb is due for a thorough disassembly and cleaning. Gunk floating around in the carb can cause intermittent issues like you describe.

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

These motors can't really get "airbound" as the carb is vented to allow any air to escape. More likely your carb is due for a thorough disassembly and cleaning. Gunk floating around in the carb can cause intermittent issues like you describe.

Even though the carb was serviced and cleaned about 3 months ago? Do they gum up that quickly or am I just unlucky?

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

These motors can't really get "airbound" as the carb is vented to allow any air to escape. More likely your carb is due for a thorough disassembly and cleaning. Gunk floating around in the carb can cause intermittent issues like you describe.

Also, now that it seems to be running right did the gunk possibly flush out? Could it be running better because there was no load on the engine? I assume that once the jet gets gummed up then it will run crappy until cleaned, is that true?

 

[oldcatamount]

Re: Possibly airbound? (1986 9.9 evinrude)

Carbs don't usually gum up that quickly but there could be a piece of fuel line (or something similar) in there. Motors will always run better on muffs because they're not working hard. I do think you are on the right track though. It does sound like you have an air leak somewhere causing those symtpoms. Be sure your fuel tank is venting correctly and look for more loose connections like the one you found already. If that doesn't help, then another carb kit job should do the trick.

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

Carbs don't usually gum up that quickly but there could be a piece of fuel line (or something similar) in there. Motors will always run better on muffs because they're not working hard. I do think you are on the right track though. It does sound like you have an air leak somewhere causing those symtpoms. Be sure your fuel tank is venting correctly and look for more loose connections like the one you found already. If that doesn't help, then another carb kit job should do the trick.

I was thinking the same thing about the carb, just seemed odd that it gummed up so soon.

 

[82rude]

Re: Possibly airbound? (1986 9.9 evinrude)

5 will get you 10 it was the fuel connection that was the culprit.first thing i look for when i come across issues like you listed.9 times out of 10 thats exactly the problem.

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

5 will get you 10 it was the fuel connection that was the culprit.first thing i look for when i come across issues like you listed.9 times out of 10 thats exactly the problem.

Just came back from the lake and still doing the same thing. Must be the carb I guess.

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

I understand that while running the engine on muffs there is no load and the engine will run better but if I am having a fuel issue (i.e- sucking air, carb, etc) shouldn't I get some of the symptoms?

 

[Fronterra]

Re: Possibly airbound? (1986 9.9 evinrude)

And the carbs being cleaned 3 months ago is what the previous owner told me, I did not get the carb done myself so now I am suspect that it even happened.

On a seperate thought, I am using Super Tech outboard 2-cycle TC-W3 Engine oil in my mix, could that be the culprit in gumming up my carb? It says it is good for all high performance outboard engines (including evinrude)

 

[ondarvr]

Re: Possibly airbound? (1986 9.9 evinrude)

You can have cleaned the carb this morning and it can be plugged up this afternoon, the time span means nothing. It may take a while for it to actually "gum up", but there can be crap introduced as soon as you plug the fuel hose back on that will plug the jets.

 

[oldman570]

Re: Possibly airbound? (1986 9.9 evinrude)

I have found that nolder rubber fuel lines and diaframs in the fuel pump will deterate and flak if ethenoal gas is or has been used in older motors. If using ethenoal gas you should replace all the fuel lines with new ethenoal resitant fuel lines. Newer rebuild kits for the carb and fuel pump are ethenoal restiant because of it. Otherwise why is there new ethenoal restant fuel hoses being made? for those that think that it dose not matter. I use the same Wally World oil in all the motors I have and work on and it works fine but smokes more that the new syntheic oils do.
Oldman570