• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Announcement Module
Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old threads or hijack existing threads. Old threads of a technical nature are like a library book, Please do not write in them.

2. Old threads should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís thread (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new thread of your own.

4. If you have a question for the original poster (OP) and the thread is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old thread.

5. By starting your own thread, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís thread. And those answers will be specific to your particular issue.

6. Please do not post to threads that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any thread that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old thread.

7. Posting at the end of any thread is considered to be hijacking the original posters thread which in turn subjects the thread to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive thread asking you not to reply to old threads. The Red banner will read: Please note this thread has been inactive for 90 days. For the best results, please start a new thread.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

1972 Evinrude 50 HP "Lark". New motor, new challenges

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts


  • 1972 Evinrude 50 HP "Lark". New motor, new challenges

    I finally had an offer come along on craigslist that I thought was too good to refuse. A fellow out here had a 1972 Chapparal 15' tri-hull that he had to get rid of due to moving to a new community that would not let him keep a boat (townhouse community, no garages). I picked up this boat for $400. It has a 72 Evinrude 50 HP "Lark" (Model 50273C). I tested compression (140 on both cylinders) and spark (good bright spark with a tester), checked the LU oil, which came out blackish, but did not show any water mixing, nor did any water come out of the LU.
    I have the service manual on order already, but just wanted to see if anyone had any words of warning about working on these motors. I see that it does not have a manual shift, but some kind of push-button arrangement.
    I cranked the motor to test compression and spark, but did not actually start the motor. The fellow didn't have a barrel to run it in, so given the price I paid I am taking a chance. I figured with those compression numbers and the spark test, If it doesn't run it would be a fuel/carburetor issue which doesn't worry me too much since my first step will be to disassemble, inspect, and clean the carbs and replace the fuel lines.

    I have had older motors up to now which are not able to use muffs. Can this motor run on muffs?

    Any words of wisdom would be appreciated.

    Rgds

    Eric

    1988 Stingray 176 SVB with Mercruiser 3.0L (181 CID) - The Ghostrider


  • #2
    Re: 1972 Evinrude 50 HP "Lark". New motor, new challenges

    Uhhhh..... I have a '73 65hp and I run it on the muffs all the time. Get ya some and see if the motor will run. Wouldn't surprise me if it needed a carb job.
    15.5 fiberglass CC, 1973 65 hp E'rude "the beast"

    Comment



    • #3
      Re: 1972 Evinrude 50 HP "Lark". New motor, new challenges

      you have good power head, but you have a hydro-electric shift lower unit. i had a 71 did not like running on muffs, best in barrel.

      notice the difference in the lower unit oil, it requires special oil.

      Hydro Electric Shift)
      (J. Reeves)

      The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.

      You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)

      In neutral, you need 12v to the "Green" wire.
      In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
      In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)

      To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.

      This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
      With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.


      also when servicing the water pump be very careful of the wires, and the grommet has to be in place or the carbs will suck exhaust thru the wire opening.
      FLORIDA GATORS
      TEBOW Country



      Please, NO PM's (Private Messages) regarding boat/engine problems. they will not be answered.
      That is what these forums are for. Post your questions, in the appropriate Forum.

      Comment

      Working...
      X