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Johnson 25hp 1979 no fuel

trynhooker

trynhooker

Regular Contributor
I've been working on this motor a few days. It sat idle for about 10 years or so.
Fuel pump and gasket replaced (no rebuild kits for these pumps), carb rebuilt today and is really clean, new plugs, new fuel and tank, compr. 130 both cyl, Had to replace most of the wiring from the main harness.
Electrical is all good, great spark etc etc.and it does run.

When I squirt some fuel in the carb, it will start fine and run a few seconds till that fuel burns off then stop. Apparant no fuel is getting past the carb. The plugs are dry after cranking, another sign of no fuel obviously.

I am thinking the reed valves are stuck/broke and isn't pulling fuel from the carb?

Would like a second opinion, eitherway, I'm pulling the intake tomorrow.
 
Yes I put a new carb gasket on it. The face is clean as I had to scrap the old gasket off. The carb has been checked twice now, completly clean as of today.
Since everything was cleaned and or replaced, including new fuel lines on motor, it leads me to the reeds... It wouldn't surprise me to find them stuck considering the thick gummy stuff from the carb..

I will check everything again tomorrow while I pull the reeds out..

I didn't consider the crank seals, esp the lower one as I've not seen any oil etc running down the lower unit.. Although I know it might not be visible...

Thanks for your response too!
 
Sadly the seloc book ids horribly wrong, doesn't even show this carb setup. Also says it's a type II carb for this year but it's a type Iv..duh
Found today the reeds are ok. Can hear the sucking when I squirt in gas. Sync is fine tho, throttle plate fully closed at no throttle etc and opens accordingly.
 
Also, I checked all the cover bolts, all tight. I just had a thought tho. I wonder how much vacuum is being lost with the intake plastic cover off? I've never had an engine NOT run at all with it off?
 
No go on the intake cover. Plugs are completely dry, still not getting fuel out of the carb. Still pointing to not enough vacuum even tho it pulls good vacuum when it runs.
 
Does anyone know first hand this? On this diagram http://www.boats.net/parts/search/BRP/JOHNSON/1979/25E79R/CRANKSHAFT AND PISTON/parts.html

is pc. 10 the same seal that's shown on pc. 11?

If replacing the lower seal, seems all that's needed is, 10, 12, 13, 24, and the powerhead to lower unit gasket.
Been a long time since I've seen one apart and wasn't positive.

I don't like replacing parts without a known reason, but on this motor I cannot see the problem.
 
Hey, have a look at this pic, http://www.boats.net/parts/search/BRP/JOHNSON/1979/25E79R/CYLINDER AND CRANKCASE/parts.html

Look at where 27 connects below the front of crankcase in 5 to top of crankcase in 5.
This engines has a hose from the bottom over to the bypass cover where 92 is connected.
I'm not sure I have a nipple on the front top and if it's there I haven't noticed it?
They aren't showing where 92 is connected.
If there is in fact a nipple there open ended, would that maybe be causing the problem.
 
Got her all fixed up today!
Seems as even tho the idle tube allowed fuel thru it, it was still not completely clean. Neither was the main tube.
I made sure it was completely clean today. Started right up afterwards..
 
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