Johnson RDE-17R?

[crosbyman]

Mumbles could you do an actual current draw … in series…. measurement of that coil under a 6 volt supply.

at .9 ohm coil resistance with a 6volt supply would draw 6.6 amps…. seems like a lot ..maybe

the selenoid ballast resistor could be a simple automotive light bulb…. say 30 watts at 6 volts will allow a 5 amp draw.. probably close enought for that selenoid to pull up. good enough for a test anyway.

A solid resistor would be more appropriate of course being more tolerant to engine vibrations..

Telephone companies used bulbs extensively in the 60-70,s as current limiters (ballast lamps) in central offices. Anytime something got shorted out (load wise) the bulb would simply come on…. saving a blown fuse down the road.

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[wyo307]

OK everyone I am really enjoying the electrical talk, it takes me back to my electrical engineering classes in college.

I finished tearing the motor down last night and was able to get a look at the crankshaft seals. They both look to be in good condition and are not leaking currently but if these are the "bad" seals I will replace them while I am here. So can someone please identify if these are in fact the "bad" seals?

Here are two pictures of the top crankshaft seal:

And here are two of the bottom crankshaft seal:

Thanks again for all of the help and good thought provoking conversation.

[wyo307]

Ok so just to be on the safe side I ordered a new seal for the top and bottom of the crankshaft, a cab kit, a lower unit kit, new coils, new condensers, new points, new spark plugs, new exhaust gasket, new impeller and the plastic pin for the throttle linkage. While this thing is completely torn down is there any reason to crack the crank case? I don’t have a compression tester but it felt like it had good compression before tearing it down. Visually looking through the spark plug holes it doesn’t look bad at all. Now I just need a new pump for my parts washer and we will be back in business.

[olcah]

Yes, looks like you have the crappy seals top and bottom.
I am working on an RDE-18. My bottom crankshaft seal is the carbon type and was broken into pieces. I ordered a new carbon and have the other parts for the bottom but could not find a new crappy seal for the crankshaft top . The Johnson parts catalogs for RDE-18 and RDE-17R identify the crappy top seal as #303804. Where did you order that seal?
Also It appears that the crappy top seal is pressed inside the bearing body (vs pressed against the crankcase bore). It would be easy to damage the bearing by trying to drill and pry out the seal. The Johnson tech manual page 323 says to use special tool #377067. Do you have access to that tool?
Thanks.

[olcah]

From marineengine.com for RD-19 (1957) the top seal is #321467 or 18-2060 aftermarket but how did you determine that number also applies to RD-17R (1955)?
Thanks.

[chris-p]

321467 is the new ss number. 303804 is the original number. Same seal, order with either number. I have a few dozen on hand.

[olcah]

Chris, Thank you for the info.

[wyo307]

As Chris stated I just ordered the 321467 seal for the top and bottom. I don’t have any special tool but I don’t think that it will be too bad to pry them out of there. We will see, all of my parts should be here this week.

[wyo307]

Sorry to resurrect my old thread but I ran into something that I had some questions on. This is my choke solenoid off this motor and I noticed that it has a hole in the epoxy in the end of it where it looks like it got hot at some point. Do you guys think it is fried? I have no way of checking it right now (no 6V battery or the proper ballast to use a 12V) so I don’t know if I should find a new one or not. If this is good I will need a new rubber boot for it but I see Peter has them on his website so I can order it with the paint.

[crosbyman]

just try a car battery 12v and hook up a common car bulb (48 watts or so ) in series with the selenoid . it will drop the voltage down per Ohms law and allow at least a few amps to pull the selenoid for a few seconds. In theory anyway… 💡

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