No acceleration 1982 70hp Johnson

[Notchcraft]

I recently bought a boat with a 1982 Johnson 70hp. It had been sitting for about 2 years, the owner said it ran good last time he used it. I took it to the lake and it started fine, idled low but when I would put in gear and opened the throttle it would just die.

He is the list of things I did after that,

Checked the compression, 120psi on all three

New Champion plugs gaped to 30

Rebuilt the carbs with complete carb kits, new gaskets, checked floats, and levels, made sure throttle cable was opening the carbs and choke was working

Tested all fuel line connections, hose, bulb, and tank

Running premium 92 non-oxy gas

Tested it in the driveway with mufs, no problem (I know it's different in the water) Took it to the lake thinking it was the carbs cause they were dirty and problem solved.

Same thing happened, no difference. Starts fine, idles low (don't have a tach in the boat) put it into gear and it dies.

I didn't check the sync-link because I don't have a factory manual. I bought the boat to fix up and sell so I don't want to buy a $?$ year specific manual. I searched the forum to do the sync-link but nothing is listed.

Any help on this is appreciated!

 

[tashasdaddy]

Re: No acceleration 1982 70hp Johnson

welcome to iboats

did you remove the jets a clean them when you did the carb?

did you replace fuel lines, do some reading here. http://forums.iboats.com/showthread.php?t=299680

 

[Notchcraft]

Re: No acceleration 1982 70hp Johnson

I removed the jets, replaced the needle and seats, removed, cleaned and replaced the welch plugs. I didn't replace the lines, they looked good and I don't use the ethanol enriched gas, just the "off road/marine use only" gas.

 

[kenmyfam]

Re: No acceleration 1982 70hp Johnson

Sounds like something is restricting the fuel flow somewhere. Especially if it will idle as long as you want it to until you ask more of it.

 

[Numlaar]

Re: No acceleration 1982 70hp Johnson

My 70HP is doing the same thing... hit the throttle and it dies, will idle all day long.... can burp the choke to get through the "bog" and its ok, but I'm worried I would be running it lean like that and burn a piston...

Sorry I dont have much advice, here's my thread if you want to see all the things I have tried so far, and some other feedback: Clicky

If you do find a solution, PLEASE let me know.

 

[Lion hunter]

Re: No acceleration 1982 70hp Johnson

Did you pull the fuel pump and check the screen and diaphram? I know you did the carbs and the lines looked good but whatever was in those lines and fuel pump after sitting for 2 years went right back into your carbs when you started it. At a minumum I replace or clean everthing from the inline fuel filter to the carbs when I do a rebuild.

 

[Notchcraft]

Re: No acceleration 1982 70hp Johnson

Checked the screen and the diaphragm. I think i'll replace the lines, check the carbs again and probably rebuild the fuel pump and see what happens.