’56 RDE-18 doesn’t want to start

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  • Avatar
    PederJoWI


    Replies: 3
    Topics: 1
    #208492

    I recently rebuilt the ignition (new coils, condenser, points, wires, caps, and plugs – sourced at sierra), carburetor, and pressure tank for a known 1956 Johnson 30hp (RDE-18). My dad has owned it since the late 60’s and it worked up until it was placed in storage about 20 years ago (albeit with a bit less power towards the end – probably from the weak spark and bad adjustment on the advance mechanism we found while working on it).

    At first attempt to start, I had no response at all. There was a leak in the fuel line connector and I sent that in for a proper rebuild. It is now sealed and we tried again. Using some starter fluid in the intake this time, we got it to kick over right away. We also managed to get it running for 2-3 seconds many times, but never for longer than that. But it sounded normal and “wanted” to run – burning fuel, not just the starter fluid. I suspect an issue with the carburetor and/or the mix. It seemed happiest (most eager to start) with the low speed jet adjustment turned to lean and the choke closed or partially open (I think I had it full open on my first day of attempting this) so I wonder if something is causing an overly rich setting. Maybe it’s flooding?

    Plugs did have a little bit of dark wet stuff on the threads and cone when I pulled them out to check on them.

    I’ve since checked the default setting on the low and high speed jet adjusters (low should be 1 full turn out from seated and high at 3/4 turn according to my manual) and they were both pretty close to where they should be.

    I am new to outboard motors, but I work on my ’78 bmw motorcyle so I’m familiar with points ignition and carburetors and such. I am confident in the rebuild on the carb, but I know things can be easily amiss there.

    What should be my next steps? Pull the carb and re-check it? One thing I didn’t think to check was the buoyancy of the float – would a sinking float cause hard/non-starting?

    Might it be an issue with the spark advance settings? We followed the book upon assembly and I’m pretty confident we got it right, but again, I imagine it’s easy for something to get a little off there.

    Thank you all for the time and attention. I would very much appreciate resurrecting this old motor. It hangs off the back of a Glen-L TNT that my dad built in ’68 as a teenager, we rebuilt together when I was a teenager, and I just fixed it up and gave it new topside decking after 20 years of sitting on a trailer in the backyard. My siblings and I learned to ski behind it and I have many fond memories with this old boat. Hoping to make some new ones with my son and nieces.

    Avatar
    jeff-register


    Replies: 1180
    Topics: 49
    #208495

    NEVER EVER use starting fluid on a two stroke. You just wiped the bearings clean of lubercant. Does your fuel bulb pump up hard? Try removing the carb bowl drain plug to see if your getting fuel, tank clean? fuel hose brittle & leaking. I once had a old line flaking off from the inside & clogging ports.
    Bet your capacitors are bad too.
    These guys use cork floats in the carb & they go away with time. Something to check,

    1 user thanked author for this post.
    frankr
    frankr


    Replies: 5239
    Topics: 48
    #208498

    Have you checked compression? Results? Does it have 5/16″ spark on both cylinders?

    Avatar
    PederJoWI


    Replies: 3
    Topics: 1
    #208504

    Jeff, thanks for the heads up on starter fluid. Guess I got some bad advice. Fuel line and filter are new. Tank was cleaned out and rebuilt. It’s a 2-line hose and It does pump to hard – the glass bowl is definitely receiving fuel. I haven’t pulled the carb yet, so can’t say for certain about the float bowl. I’ve wondered about the cork float. What do you mean by capacitors?

    Frankr, I haven’t checked compression. It feels like plenty, if that’s helpful to know. By 5/16” spark, is that the distance it can arc while grounding one and holding one out from the engine block? The spark jumps, but I don’t know if it was that far.

    outboardnut
    outboardnut

    US Member - 2 Years
    Replies: 695
    Topics: 461
    #208506

    I’m confused did you buy a carb rebuilding kit

    frankr
    frankr


    Replies: 5239
    Topics: 48
    #208507

    Yes arc gap. Even weak spark will fire starting fluid, but not run. If the carb is filling, I seriously doubt lack of gas is the problem. Well, ok, possibly too much gas?

    Avatar
    PederJoWI


    Replies: 3
    Topics: 1
    #208512

    Yes, I bought a rebuild kit with gaskets and new float jet (not sure if that’s what it’s called – the little one that lets the fuel in). I just pulled it apart and checked the float – it floats fine – and that fuel is passing through the glass bowl into the carb float bowl. It all checks out.

    I’m confused did you buy a carb rebuilding kit

    bobw
    bobw

    US Member - 1 Year
    Replies: 1072
    Topics: 41
    #208517

    When you opened up the carb, how was the gasket on the high speed nozzle? Did you take the carb off the motor and clean out all the passages?

    Bob

    1954 Johnson CD-11
    1956 Johnson RD-18
    1958 Johnson QD-19
    1959 Johnson QD-20
    1957 Evinrude Fastwin 18

    "Every 20 minute job is only a broken bolt away from a 3-day project."

    Avatar
    fleetwin

    US Member - 2 Years
    Replies: 3313
    Topics: 49
    #208531

    Yes, I would start by rechecking the simple stuff…I realize you worked on the ignition, but you need to ensure you are getting strong spark on both cylinders. This is an electric start engine, correct?

    Avatar
    PederJoWI


    Replies: 3
    Topics: 1
    #208576

    Thanks, everyone. The carb is clean – I did a rebuild with a kit last winter, cleaned everything, cleared passages and replaced gaskets. I pulled it yesterday to check it and it’s all still clean and intact. We also pumped some fuel through the line to ensure that it was getting into the float bowl. (Checked buoyancy of float as well and it’s just fine.)

    Bobw, when you say the gasket on the high speed nozzle, do you mean the needle that passes through the front with the knob or the jet that goes up the center from the float bowl? The jet gasket is fine. The high speed needle has the metal collar and gasket sort of stuck in that threaded hole. The metal collar is seated where it should be and the gasket appears fine. Honestly, this one may well be an old gasket. I couldn’t pull it out yesterday and I may not have been able to when I did the rebuild. (Can’t remember if I replaced it, but I don’t have the replacement for it, so I’m maybe 50/50 on this.)

    I am now suspecting spark, given the knowledge shared here. It doesn’t arc over 1/4”. Unfortunately, one of the short bolts in the flywheel snapped on me as I was installing it yesterday. Ugh. It isn’t seized, so hopefully I can extract it soon. (It’s one of the three around the center nut, a hole used for the flywheel puller.) this being the state of things, I can’t examine the ignition until this is sorted. I recall that getting the magnet to pass the coils as closely as possible without touching them was a bit tricky. Could be that I have them adjusted too far away from the magnet. This would make for weaker spark, wouldn’t it? Reseating the wires seems a reasonable step also. To be clear, there is bright spark on both cylinders and both will arc to block when held slightly away – just not as far as suggested.

    Fleetwin, we just wired up the starter yesterday (unused since early ‘70’s). It spins! Question on this, though. We pulled the spark plugs (and grounded them to the block) to test the starter and the starter gear went up and spun the flywheel but didn’t go back down when I released the button. I see threads on the starter shaft and I wonder if the force of the flywheel, under power, sort of kicks the starter gear back – against those threads to drop the starter gear out of the way? Is this how it works? Or should that starter gear drop back down (clear of the wheel) on its own when released? It is still in the up position. It spins freely by hand and spins the wheel on subsequent pushes but remains up. At some point, we’ll get the flywheel off to check ignition and drop this back into the water tank, but I’m hesitant to test my theory of the motor kicking it down when it fires.

    Thanks, everyone!

    Avatar
    fleetwin

    US Member - 2 Years
    Replies: 3313
    Topics: 49
    #208584

    Yes, it is perfectly normal for the starter pinion to stay engaged when cranking with no plugs installed. It is the kick of the engine or compression that bounces the pinion out of the flywheel…Be careful with the starter motor, it may be a 6 volt starter…Using 12 volts for quick cranks is OK, but extended cranking with a 12 volt battery will kill it.
    What type of puller are you using? Is it the OMC puller? Those flywheels are tough to get off, using some other puller is bound to cause trouble and make removal more difficult. Yes, you will need to get that broken bolt removed before attempting to remove the flywheel again…
    I don’t want you to pull that flywheel off just on a hunch, please confirm you have weak/no spark before getting in there again. Sometimes those inline neon spark testers are handy to check spark while cranking/running…
    The flywheel must be properly torqued or you will shear the key which will kill the spark and make flywheel removal even more difficult..

    olcah
    olcah

    US Member - 1 Year
    Replies: 415
    Topics: 82
    #208585

    After you have checked out your ignition with a gap tester,using the starter but NOT starting the motor maybe this will help:

    I had a 12 HP Sea King and later a RDE18 that did not want to start or run. They would fire then run terrible. Solution was that the carb needles needed more packing rings. Often it takes 3 rings per needle. Air was passing the needles and the motors were running lean. I would try one or two more packing rings to each needle and in tightening the packing nut assure that the lock nut is down against the packings. See how deep the packing nut is into the threads. Not too shallow, you do not want to strip the carb body threads.

    WRT the starter it sounds like you need to oil the Bendix drive. I have found on four different RD18s that starter drive always retracts regardless of whether the motor starts. Fleetwin has way more experience and is far more knowledgeable so maybe I am wrong but that is what I have seen. Test it without starting the motor but with plugs in.

    BTW if no one has mentioned it, do not start the motor without water to the pump. Running dry will destroy the pump impeller.

    Mumbles
    Mumbles

    Canada Member - 2 Years
    Replies: 4529
    Topics: 432
    #208589

    The RD and Big Twin carbs don’t have a seal or gasket on the nozzle. It’s a machined fit.

    Here’s a parts manual for you.

    Mumbles
    Mumbles

    Canada Member - 2 Years
    Replies: 4529
    Topics: 432
    #208590

    I’ll try that again another way.

    Johnson-1956-30HP-RD18-RD18E-RD18C-Parts-1

    bobw
    bobw

    US Member - 1 Year
    Replies: 1072
    Topics: 41
    #208593

    The RD and Big Twin carbs don’t have a seal or gasket on the nozzle. It’s a machined fit.

    Here’s a parts manual for you.

    Well, that’s strange. I had a parts list when I did my RD restoration last year and saw in the carb diagram there was no seal or gasket on the nozzle. But when I took my carb apart, there was a gasket on the nozzle and it took a new gasket for the carb bowl and upper body to seal up together.

    RD18-Carb-Opened

    Bob

    1954 Johnson CD-11
    1956 Johnson RD-18
    1958 Johnson QD-19
    1959 Johnson QD-20
    1957 Evinrude Fastwin 18

    "Every 20 minute job is only a broken bolt away from a 3-day project."

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