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  1. #1

    Default 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Hello,

    I appreciate any help I can get - I am not the most mechanically inclined but I can do very basic engine repairs.

    I have an older (late 80's) 50 HP Evinrude tiller motor. It has worked great for years. Recently after being stored for a while I took it out and immediately noticed it was moving much slower than normal. The engine doesn't seem to be reaching as high of rotations per minute in Forward.

    The obvious answer would be the carbs need to be cleaned, but the engine clearly revs all the way up in neutral and reverse.

    That's why I'm here. I'm wondering if someone has seen this problem before or knows how to fix it before I start figuring out how to pull the carbs out. Just seems weird that it would work fine in reverse and neutral but not in forward.

    Thank you much!

  2. #2
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    In neutral there is NO LOAD and the motor would rev up on just 1 cylinder so that means nothing.-----In reverse there will be lots of exhaust in the water and that also reduces the load.------Do a compression test first.-----Then check for spark on both leads.-----Do not run it any more until you determine the problem.-----If one carburetor was partially plugged you would be starving 1 cylinder of oil as well.-----Sounds like it is running on 1 cylinder.

  3. #3
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Bingo. Carb.....one of them could be plugged.....especially if stored with ethanol laced fuel. ALWAYS run engine dry on fuel before laying up. After it dies, choke it and/or prime the last of fuel out of it. They will rev up with no load if high speed/main jets are plugged or partially plugged....why? Loading the motor requires more fuel.

  4. #4

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Quote Originally Posted by timguy View Post
    Bingo. Carb.....one of them could be plugged.....especially if stored with ethanol laced fuel. ALWAYS run engine dry on fuel before laying up. After it dies, choke it and/or prime the last of fuel out of it. They will rev up with no load if high speed/main jets are plugged or partially plugged....why? Loading the motor requires more fuel.
    I have a side question. When running the carb/fuel lines empty of residual gas, I have been sitting at the dock in neutral. Does it matter if I run at idle speed or can/should I run higher to speed up the process?

  5. #5
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    I feel it doesn't matter. Just get that fuel out. Have motor as level as possible.

  6. #6

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Keep in mind you just ran it out of lubrication also

  7. #7
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Nope-----When a 2 stroke carburetor goes empty there is lots of oil all over the parts and no damage is done !!!!-----There are no warnings on portable fuel tanks about running a tank empty.----Never read a warning in an owners manual either.-----Just more proof that 2 stroke lubrication is not well understood

  8. #8
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Amen Racer....how long YOU been playing this game?

  9. #9

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Quote Originally Posted by racerone View Post
    Nope-----When a 2 stroke carburetor goes empty there is lots of oil all over the parts and no damage is done !!!!-----There are no warnings on portable fuel tanks about running a tank empty.----Never read a warning in an owners manual either.-----Just more proof that 2 stroke lubrication is not well understood
    So you are saying their is still lubricating oil in the carburetor?

  10. #10
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Nope------All the precision parts INSIDE the engine are coated with oil !!!-----And that oil does not disappear in an instant when just dry air with no fuel starts going through a crankcase / cylinder.----Just more proof that oil and lubrication is not well understood INSIDE a 2 stroke engine !!

  11. #11

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    We,everyone but you,were talking about running fuel out of the carburetor.
    Only you brought the lubrication of a 2stroke

  12. #12

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    We,everyone but you,were talking about running fuel out of the carburetor.<br>Only you brought the lubrication of a 2stroke

  13. #13
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    The oil which is mixed with the gasoline stays mixed. The vaporized mixture is combusted, the rest......still sticking to everything else.....provides protection and lubrication. Case in point: How in Gods green earth can there be combustion anywhere in the crankcase, bearings, or even piston rings? When storing a motor, I always squirt a little 2 stroke oil in the cylinders and spin it over. Why? First, the cast iron sleeves are the first to pick up any rust, and secondly, you will want to put new spark plugs in at the start of a new season anyway......a twin cylinder will cost you all of 7 bucks for Champions.
    Cast iron is used for cylinders because it is pourous, good cast contains a larger amount of nickel.....why? This adds hardness, and resists rust. The fact that cast is pourous.....it retains oil. Case in point: Skillets!
    Last edited by timguy; 08-10-2020 at 10:42 AM. Reason: Add info

  14. #14
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Sorry---But post #6 clearly states that----" you just ran it out of lubrication also "----So Rw what did you mean by that statement ??

  15. #15
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Furthermore, friends.....I've been running fuel dry hundreds upon hundreds of times on dozens of outboards over the last 55 years. Guess what? If I ever hurt an outboard, I would know about it. Case in point: 1965 Evinrude Fisherman......3500 hours, mostly 64:1 on Amsoil synthetic......never ever tasted ethanol or any additives. Run dry after every fishing trip to Ontario wilderness. I DONT WANT a new outboard. Why? Don't need any stress or headaches. Run and live by what I trust, what I love, ......walk the talk.
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    Last edited by timguy; 08-10-2020 at 01:13 PM. Reason: Add photo

  16. #16
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Have one of those 1965 model 6 hp motors laying in my yard.---Own many other 6 hp models too.---Just bought 4 new cranks for those motors for future projects.-----They were " on sale " and with future parts in doubt I will be able to fix any one of them !!

  17. #17
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Just picked up a 1976 with lost recoil and head gasket blown across.....you know the old story. Still sell em like hot cakes up here in MN, get more for em than they sold for when new. You must love em too. Quality, lightweight, simplicity, reliability, durability, and value.....what's happened to this world, Racer?

  18. #18
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    It is difficult to convince the modern world that they do not -----" build them like they used to "-----I just love the 5.5 / 6 HP model from 1961 to 1979 , just sweet running motors when properly maintained.

  19. #19

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    I had a small circa 1998 Tohatsu on a sailboat I owned. I ran the carburetor dry every time I used it and never had a problem. In the winter I would put it in the lazarette and not worry about it until the spring when it was time to go racing. The joke among the crew was would it take two pulls or three to start it. One spring it wouldn't start (2003 or so) and I did have to take the carburetor apart to clean it. I didn't see anything suspicious but it has worked ever since. I'm not saying it never needed work either. The exhaust tube rusted out, the carburetor linkage had a habit of loosening up and once the carburetor top came unscrewed. I will add there was always a film of two stroke oil under the covers besides, the stuff does not all get burned with the gas. I see the boat regularly and that engine is still running like a champ.

  20. #20
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    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    Well a 2 stroke should last 100 years when used on a sailboat to go racing.-----Provided my skipper with a 1962 Johnson 3 HP long shaft for racing.-----Filled the tank before going out on a 24' boat ( Russian built )------We took the motor off the transom and hung it on the mast down below while racing.-----Fun times.

  21. #21

    Default Re: 50 hp Evinrude works prefect in reverse and neutral but has low RPM's in Forward

    lot of delivery hours on that motor. The point I was trying to make was that running them out of gas doesn't hurt anything.

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