1974 70HP Evinrude: hard start, wont idle, dies in gear

[sharkscove808]

I have a 1974, 70HP, Evinrude Outboard Model#70473M. I bought it from a guy who said it ran just fine last year, he had it winterized and then it sat for just over a year. I emptied the old fuel and put fresh fuel/oil in the tank, it will start when choked but will only run with the warm up lever up and even then its only for 10 seconds or so, then it dies. The few times i got it running for more than 10 seconds, it died as soon as i put it in gear. I pulled the plugs, they looked pretty good, i pulled the filter and it looked clean and free of debris, i checked all three plugs for spark and they all had a strong spark (visible in bright sunlight), all the butterflies close evenly on the carbs and the linkage appears to be functionng as it should. There is an older style brass valve in the fuel line that drips a small amount of fuel when you turn it, it was used by the previous owner to run 2 fuel tanks, i only have one tank hooked up, the other fuel line just hangs there. Any ideas as to why it would do the things mentioned above? What should i do next?
IDEAS: New fuel lines from the tank to the filter? New plastic tank instead of the original 1974 metal gas can/tank? Remove the valve and go with one fuel line???? Any help would be greatly appreciated.

thanks and happy boating.

[75-JOHNSON]

did you try taking out the screw plug at the bottom of the carbs to see if there filling with fuel

[bolter15]

You've got clogged carbs.

Old school: Soak the carbs in gas over night before you try and start the engine.

Garage mechanic school: Remove the carbs from the motor and disassemble them. Work them over with a can of carb cleaner and compressed air, and maybe a brush fashioned from a fine stranded copper wire chord.

Shop mechanic school: Buy a carb rebuild kit for each of the carbs on your boat, dissassemble and soak the carbs in solvent then reassemble using new parts.

Good luck

[sharkscove808]

I will see if i can located the screws to check the carbs for fuel, if that doesnt work, i'll work on unclogging the clogged carbs....starting with the old school way and moving on from there if that doesnt work.

thanks guys.

[sharkscove808]

Forgot to ask, where can i get a carb kit for those carbs? All i know is that the engine is an Evinrude Model#70473M.

[tashasdaddy]

go with one fuel line, until you have all the problems worked out. sounds like a case of ethanol poisioning. read the great info here ethanol, carb cleaning, timing etc http://forums.iboats.com/johnson-evinrude-outboards/top-secret-file-updated-8-1-2012-a-299680.html

i suggest ordering 3 of these, http://www.iboats.com/mall/partfinde...****=287936711

[sharkscove808]

looks like the backyard mechanics way solved the problem. I pulled the carbs, soaked em' and cleaned em' with carb cleaner, re-installed em' , the boat started, idled and went in and out of gear just fine. I still need to test it under load on the lake but it would appear to be a complete success at this time.

thanks iboats and those that helped.

Happy Boating.

[sharkscove808]

Well, that was some short lived glory. I went out today, started the boat in the driveway...it fired up instantly and ran smooth. I took it to the lake, put it in the water and barely got it started. Once it was running, i took it to my dock, turned it off and that was about it, getting it started again was like pulling teeth and when i do get it started, it wont stay running, its just as if i had done nothing to it. Im about ready to go get a new four stoke fuel injected motor and be done with it.

[sharkscove808]

Also forgot to mention that when i was looking at the carbs while it was running witht he cover off, i noticed that the "Screw plugs" (thats what they're called on an exploded view of the carburator i found on the net) were not tight or staying put, they were vibrating around and turning in and out on there own just from the vibration of the motor. What are those for, should they be adjusted or tight or ??

[Daviet]

If you are talking about the 7/16 bolt in the front of the float bowel, yes they should be tight. There should have been new gaskets in your carb kits to seal them to the bowel.

[sharkscove808]

Actually its not the float bowl screws, its the screws at the top center of each carb right above the throat of the carb.

[Daviet]

Actually its not the float bowl screws, its the screws at the top center of each carb right above the throat of the carb.

I think you might be talking about the idle passage plug screws. Yes they should be tight. There should have been a seal washer in your carb kit.

[Daviet]

I was rereading your post, you said you overhauled your carbs. And later you said the idle plug screws were loose. Did remove the idle orifice behind the idle plug screws to make sure they were clean? Did you get them back in tight? Loose idle plug screws could allow excess air into the idle circut. Just thinkin.

[bifflefan]

I have a 1974, 70HP, Evinrude Outboard Model#70473M. I bought it from a guy who said it ran just fine last year, he had it winterized and then it sat for just over a year. I emptied the old fuel and put fresh fuel/oil in the tank, it will start when choked but will only run with the warm up lever up and even then its only for 10 seconds or so, then it dies. The few times i got it running for more than 10 seconds, it died as soon as i put it in gear. I pulled the plugs, they looked pretty good, i pulled the filter and it looked clean and free of debris, i checked all three plugs for spark and they all had a strong spark (visible in bright sunlight), all the butterflies close evenly on the carbs and the linkage appears to be functionng as it should. There is an older style brass valve in the fuel line that drips a small amount of fuel when you turn it, it was used by the previous owner to run 2 fuel tanks, i only have one tank hooked up, the other fuel line just hangs there. Any ideas as to why it would do the things mentioned above? What should i do next?
IDEAS: New fuel lines from the tank to the filter? New plastic tank instead of the original 1974 metal gas can/tank? Remove the valve and go with one fuel line???? Any help would be greatly appreciated.

thanks and happy boating.

Carb Rebuild
mine was the same, rebuild carbs, link and sync, adjust timing. runs like new.

[sharkscove808]

I was rereading your post, you said you overhauled your carbs. And later you said the idle plug screws were loose. Did remove the idle orifice behind the idle plug screws to make sure they were clean? Did you get them back in tight? Loose idle plug screws could allow excess air into the idle circut. Just thinkin.

I had pulled the carbs, soaked em' and cleaned em' with carb cleaner, not overhauled them. I have a guy coming over Wednesday to rebuild them completely so they're done right. Ive rebuilt just about everything on the boat but carbs is something i hadnt done before...hes gonna do it and give me a lesson in the process.

[Daviet]

Please post your results, would be interested if carb overhaul fixes problem.

[sharkscove808]

I had a local mobile marine mechanic rebuild the carbs with 3 kits we got right here on iBoats.com. After rebuilding the carbs, the engine started easily and went in and out of gear without an issue, but, we havent been able to get it out in open water yet due to the weather. Hes confident that the issue was in the carbs...the compression on the cylinders was 160, 158 & 158. He said the top carb was working but not well, the middle carb was hardly functioning at all and the bottom carb did not appear to be working in any way. thats all i can post until we get it out in the water on Friday. i'll post the final results as soon as i get them.

[sharkscove808]

The carb overhaul fixed every problem, ive been running the boats for 2 weeks now and everything is fine. thanks for all your help.

[papasage]

good to hear you have it running right . i have one like it i need a prop shalft and a drive shalft for it .