1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

[TrustyJohnson]

Some friends and I recently purchased a 16' Starcraft and along with it came what we believe to be a 1962 Johnson. We can't find any identification plate on it and based on the writing in permanent marker on the inside of the top cover, it wouldn't help anyway. The writing says "1962 Top End 40 HP Lower 33 HP Johnson".

We ordered a new impellor for a 1962 40 HP motor. It turns out that the new impellor is quite a bit taller than the original we took out and wouldn't fit in the housing. Can anyone verify that there is a difference between the 33 HP and 40 HP impellors? Also, are there any tell tale signs that we have a 33 HP lower as opposed to the 40 HP? Remember that there is no ID plate or any date markings other than the permanent marker inside the top cover. Thank you in advance!

 

[F_R]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Some friends and I recently purchased a 16' Starcraft and along with it came what we believe to be a 1962 Johnson. We can't find any identification plate on it and based on the writing in permanent marker on the inside of the top cover, it wouldn't help anyway. The writing says "1962 Top End 40 HP Lower 33 HP Johnson".

We ordered a new impellor for a 1962 40 HP motor. It turns out that the new impellor is quite a bit taller than the original we took out and wouldn't fit in the housing. Can anyone verify that there is a difference between the 33 HP and 40 HP impellors? Also, are there any tell tale signs that we have a 33 HP lower as opposed to the 40 HP? Remember that there is no ID plate or any date markings other than the permanent marker inside the top cover. Thank you in advance!

As you found out, the 1962 40 has a taller impeller. The 40 also has two (sometimes 3) water tubes. 33hp has only one.

However, a 40 powerhead won't fit on a 33 midsection..unless it is a 40hp Gale powerhead, or a post-1970 Evinrude or Johnson one.

 

[Daviet]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Look and see if you can find a core plug, about the size of a quarter, on the power head with a model number stamped on it. May a least tell you what power head you have.

 

[asdasc]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

The 1962 40HP will be a RDS-24 and the 33HP will most likely be RX or RXE, -13 thru -16 from 1965 thru 1968 models.

F_R, will the 33HP lower unit bolt up to a RDS-24 mid-section? My guess is that they just replaced the lower unit on their RDS-24.

 

[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Thank you all for the replies. Where should we look on the powerhead for the core plug that Daviet mentioned? We have the 33 HP impellor ordered and upon its install should have this thing ready to go.

We have already done a compression check (~85 lbs cold), installed new plugs (gapped .030) and wires, checked/cleaned points (gapped .020), verified spark with checker (both jump 1/4 to 3/8 inch), rebuilt fuel pump due to hole in diaphragm and replaced LU lube. After reviewing the ?Awakening a sleeping outboard? thread it seems that we have pretty much covered everything except the carb, which thus far hasn?t proven to be an issue.

A couple of quick questions: When installing the impellor, it seems that the vanes need to bend a good amount to fit into the housing. Is this correct? If so, should we put some sort of oil/soap on the veins during install so that it doesn?t run dry until it starts pumping water? Finally, looking down on the LU which way should the vanes be bent?

Thank you again for the help, we?re really looking forward to getting this out on the water.

However, a 40 powerhead won't fit on a 33 midsection..unless it is a 40hp Gale powerhead, or a post-1970 Evinrude or Johnson one.

F_R, how do we determine if we have a Gale powerhead and what makes that different? Also, how can a lower with one water line work with a powerhead with both inlet and outlet lines? I'm glad that we haven't yet picked up a service manual because chances are that it'd be the wrong one!

 

[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

The number on the plug of the powerhead is 2283547. What does that tell us?

 

[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

After cleaning her off we made a discovery... an ID plate. Turns out it's a RX-10 C. This means we have a 1962 Johnson 28 HP, but what model number impeller do we need? We swapped out the 40 hp one for a Sierra model number 18-3003 and it was a bit too small to fit on the shaft. The impeller housing part number (stamped on it) is 303831 and a little research points to impeller number 18-3006. Does this jive with the info we have so far?

 

[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Well we got the correct impeller and got the boat out on the water. It seems to idle down OK after adjusting it based on the procedure posted on this forum. It does however seem to have some higher RPM power problems. I attempted to do the high speed jet tune and got it to smooth out. Still after cruising at speed for a while it seems as if the boat is slowing down. It is NOT jumping in and out of gear, which I've read would indicate worn LU gears correct? With the information I provided here can anyone give us a starting point to troubleshoot this problem? Thanks again!

 

[Daviet]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Try opening your high speed jet 1/4 turn. If that doesn't help, squeeze the primer bulb while running at high speed, if that helps you might have a fuel pump problem.

 

[asdasc]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Another thing to check is it you are firing on both cylinders. It sounds crazy, but they actually run very well on only 1, just not so much power.

Try disconnecting one plug wire and see if it makes a difference. Then try it with the other plug wire.

 

[jay_merrill]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

The early sixties ERude/Johnson 40hp motor was an outgrowth of the late fifties "Superquiet" 35hp motors. It is a very different engine than the early sixties 28hp motor, which was an outgrowth of the early/middle/late fifities 25hp, 30hp & 35hp ERude Bigtwin and Johnson Seahorse engines. The 33hp motor is yet another outgrowth of this series and shares many parts with the earlier motors. Out of all of the motors in the series, the 35hp, 28hp & 33hp motors are the most similar. As you might expect, the two motors that were closest together in manufacturing sequence (28hp & 33hp) are the most similar.

The Superquiet motors have the "fat" midsection and have multiple water tubes coming from the water pump. The powerhead, midsection and gearcase of these motors is not compaitble with the 28hp/33hp series. With the exception of things likes points, starter motors, recoil starter assemblies, etc., there isn't much on them that will fit your motor.

If you adjusted the high speed needle valve and found peak high rpm by leaning it from the reference setting, but then lost power later on, I would suspect a packing nut that was not sufficiently tight. I believe your motor has an adjustment knob on the top, port side of the plastic inlet grill. There should be a link from the knob, down to the high speed needle valve. That needle should pass through a packing nut. It has to be loose enough to allow adjustment, but tight enough not to allow the needle to vibrate out of adjustment. I recommend that you check it.



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[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Thank you all for the replies. We plan to take the boat out tonight and will test the 3 theories given. I'm hoping that it is a simple adjustment of the carb as opposed to the fuel pump (which we just put a new diaphragm in) or the spark issue. I will do my best to post back with results in the near future. Thank you again!

 

[TrustyJohnson]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

Well we took the boat out last night and here is the synopsis. Opening the high speed needle and pumping the primer bulb had no affect on WOT performance. The needles did not seem as if they were loose enough to vibrate out of adjustment either. What we did see on the way back in and it was dark enough, was a little light show coming from behind the "dash". This turned out to be sparks hoping around on the back of the ignition switch. It was too dark to diagnose the problem last night but if the two black wires from the coils were being intermittently connected by the spark, this could cause the cut out problem correct? What would be causing the spark issue though, a faulty ignition switch or one that is wired poorly/incorrectly? We will be looking into this more in the next couple of days.

 

[jay_merrill]

Re: 1962 40 HP Upper / 33 HP Lower Impellor and ID Issues

An ignition switch that is shorting the coils to ground, could definately cause problems. Replace the switch and see what happens.



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