Engine dies after a few seconds at idle has fuel puddling in carb throats

[Coltrickle]

1976 Johnson 70 hp will only idle with the high idle lever up. If I put it in gear it goes dead 75% of the time. If I make it to the high end it runs great. So I start the engine leave the high idle up for a few seconds and it dies about 5 seconds after I push it down. I have rebuilt the carbs twice. But when I look in them there is fuel puddling in the throats of them.. Is this normal?? Thanks

 

[flyingscott]

Fuel puddling could could normal depends how much. What did you set the float height at. Also do a compression test.

 

[Coltrickle]

Compression is 120 top and 124 bottom and center. The puddling is about the size of a penny, maybe a little larger..

 

[emdsapmgr]

When you rebuilt the carbs did you use an aerosol carb cleaner product, like a Gumout type, to clean the passages? Did you remove the jets for a visual inspection?

 

[Coltrickle]

I used the Oreilly brand carb cleaner. The jets in the bottom bowl seem to be pressed in so I didnt attempt to remove.(never saw a jet there before) but it looked good. Is the skinny tube that runs up the center of the large tube from the bottom of the bowl to the top of the carb for the idle circuit??

 

[racerone]

Those jets are not pressed into the bowl.---They usually can be removed with a 3/16" diameter screwdriver.--Or a special factory tool.---Or a screwdriver that has the tip modified.

 

[ThePyRo]

I had this problem on my '81 Johnson 70HP 2-stroke. I had puddling from the motor being pitched up too much. Adjusted it one notch down, and it stopped.
I also rebuilt my carbs, blew everything out with carb cleaner and compressed air. Make sure your floats are properly adjusted as well, should sit parallel to base of carb when held upside down.

Another thing I came across was at the top of the carbs there is a low speed idle needle. On my carbs it was a screw, not a needle. (if you do have just a screw above each of the carb openings, make sure the screw is all the way in and snug). If they are screws with flat ends, then don't worry about reading the following. Some older models had a needle above the carb opening to control low speed idle and fuel/air. Starting with center carb, slowly screw in 1/4 of a turn until the engine starts spitting or raises in rpms. Slowly back out screw until running smooth. Repeat for other cylinders.

Hope this helps, it took me a few trials to get it right. if you can, adjust in water or in test bucket. Running the engine off muffs isn't the same as it being in the water.

 

[Coltrickle]

Thanks racerone and ThePyRo My idle circuit jet is a small orifice type that is in behind a larger screw in the top of the carb. i will remove the carbs again teardown clean and insure the floats are correct.. I did not adjust the floats when removed.. I just re-installed them and didn't pay attn to there setting.. Thanks again gentlemen will advise!! Also, i have access to ultrasonic cleaning tanks at my work.. Would it hurt to D/A the carbs and put the housings in the cleaner.. It just a mild detergent solution?

 

[ThePyRo]

I had mine done in the ultrasonic cleaner at my buddies shop. Help with a lot of build up. I didn't want to scratch or sand anything because I was afraid of messing up how the seals sat. At the top of the carb once u remove that screw the jet can unscrew. The rebuild kit should have a small red oring /plug that stops it from backing out once adjusted. Clean the jet and channel out good, real small pin holes in there that get clogged up easily. Let us know how you make out.

 

[Coltrickle]

Will do.. Thanks again!

 

[ThePyRo]

So, Coltrickle how did you make out with the carbs?

 

[racerone]

PyRo-----There are no carburetor mixture adjustments on the 76 model 70 hp.

 

[Coltrickle]

I have not yet tore them down... Will be on the to do list tonight!! Let you know in the morning how it goes

 

[Coltrickle]

ThePyRo I removed the carbs today and the floats were about an 1/8" or more to high.. I disassembled all three and other than the float height the top carb main jet was about half the size it should be.. After spraying carb cleaner through the carbs and blowing them out I reset the floats and reinstalled onto the engine. No more fuel puddling in the carbs. Now she will fire up in the barrel and purr like a kitten.. However if I put it in reverse it will run all day idling in gear and will also rev very well, when I put it in forward gear it will go dead at idle. I have to move the throttle up a little to keep it going and its also a little slow revving In gear. All this is of course in the barrel.. Any ideas on what's next?? Thanks gentlemen for your replies

 

[S.A. Baker]

Increase the idle speed in gear in the water!

 

[scrapper042000]

floats level ,there are no adjustable idle mixture screws on these ....when you put kits in ..did your kits come with the little wire retainer that hooks from the needle to the float ? number 1 problem on the ones I have done (9 sets this year ) also ,one carb not contributing can be isolated by spraying into the front of the carb one at a time if it dies its good ,if it speeds up ,then theres your lean cylinder do this carefully and yeas have the motor fairly level ......if a motor spits when it dies or kicks back its usually lean ..or your carbs are not synced ......and check your marks on the cam roller by the carb ,should be a spot that says start ....I don't have the diagram here for the link and sync but I could find it if needed .....also make sure you have no air leaks (fuel leaks ) when you prime up the motor slowly the primer should be mostly firm and you should not see any fuel leaks anywhere ,otherwise fix those first ..........usually if your carb throttle plates are not in sync the motor will kick or shake side to side because you have one cylinder trying to run faster or slower than the others due to the postion of the throttle plate if its not open the exact same as the others at idle

 

[Coltrickle]

Thanks scrapper042000 my kits did have the wire to hold the float needle to the float. I looked at the carbs and it appears that one plate may be a little further open or past full open but not real sure.. Could I set them all at full closed and fix this??

 

[Coltrickle]

I adjusted the carb butterfly plates and now they are all spot on.. I did not mess with the adjustment from the linkage to the timer base because I'm not sure if the spec.. I set the idle in the barrel but when I put it in the lake I needed to raise it a little.. After this it no longer goes dead when out into gear but it still has that dead spot about midway through the throttle.. If I slowly go through the throttle it will die before starting to plane out.. If I just go full throttle it has a hick up but will skip through it and plane out to run perfect!! Getting there but still some issues!!

 

[Coltrickle]

So today I pull the plugs just to make sure that all cylinders are getting fuel and all three plugs appear to be rusting on the ends.. And 2 of 3 had a white almost snot like looking crud on them.. I used a rag to wipe them off and it looks like mud on my rag. I guess a combination of either water or fuel and some type of rust.. Any thoughts??