Leaf plate

[hgxsilver]

Hi everyone. I have a 58 johnson Rds20. Idles good. Had it on the water yesturday trying to get it tuned. Bogs out past trolling speed. I’ve cleaned the carbs, replaced the plugs, checked ignition parts good, reeds are good, adjusted bowl, still running super rich no matter how the needles are adjusted until it no longer starts. Haul it home to have black I burnt fuel drip out of the water drains in lower end. Ordered a carb kit to make sure I have all new seals and packing nuts etc for carb. Any ideas? Running 24:1 as it’s old. As well what is the small leaf plate at the bottom of the powerhead used for? Tiny thing bout an 1.5 inch square. Thanks

 

[F_R]

They are crankcase drain valves, nothing to do with high speed operation. Are you sure about the "good" ignition?

 

[hgxsilver]

I've adjusted the points to .02, measured the coils getting around 6k ohms, and the condensers I have concluded with my fluke meter to not leak. I would suppose the coils could break downs they heat up while in use.

 

[racerone]

Condensers will fail too when warmed up.-----Answer this important question.-----Does spark on your motor jump a gap of 5/16" on both leads when motor is cold , yes or no ?---When it is warmed up, yes or no ?

 

[hgxsilver]

I would have to say yes. I had checked spark initially in the garage while in a tub. I cannot say for sure for when its warm i.e. take them out after nice n warm to do the same. After doing some service manual checking around I noticed that the cam follower is touching the cam prior to it aligning up with the projection, and the throttle lever needs to be adjusted as well. I would assume this has some influence concerning my problem.

 

[kbait]

If your motor uses a fuel pump, a cracked diaphragm would allow raw fuel to enter the cylinder it draws it’s pulse from. If you can keep pushing fuel after primer bulb is firm, that’s a likely issue(or float valve not sealing).
Good luck!

 

[Tim Frank]

I would have to say yes.

How are you checking for spark?
If you are using a purpose-built spark tester and the spark will jump a 5/16" gap as per post #4, hot and cold, then the answer is simply "Yes".

If by chance you are grounding the plug on the block and seeing "a nice spark", the answer is "No".

If the answer is a clear "Yes" then a compression check is your next step.

 

[oldboat1]

I After doing some service manual checking around I noticed that the cam follower is touching the cam prior to it aligning up with the projection, and the throttle lever needs to be adjusted as well. I would assume this has some influence concerning my problem.

That is worth exploring. The wheel should not contact the cam until it lines up with the mark on the cam. Until then it typically rides free (idle). If the carb is opening before the timing is advanced (the link and sync exercise), I believe you would be flooding the engine.

Unfortunately, I don’t recall how the link and sync is done on the ’58 — thinking via the link and collar on the side of the block, but may be wrong.

 

[hgxsilver]

Beside my fuel pump diaphragm being a little used there are no cracks but I am looking into getting a kit to bring it’s “spring back”.

I will I’ll try to set up the spark tester at that gap, I do have good compression. Around 110psi each.

I have the setup process for the cam follower.

Looks like Ike I have a few things to check out. I’ll get back with some results.

 

[hgxsilver]

After I did the link n sync the boat ran great for a day. I discovered that aluminum sleeve inside the low speed needle came free so I could no longer actually set the needle as both just rotated. I managed to use the outside brass but to hold the needle in place for that run. Today I went for a good run but then the motor started to shudder like it was running lean. I putted home to see that the motor was very warm. New impeller too. I’m waiting on a carb kit till Tuesday so I will switch out that gear. Also I’m running champion J6C plugs for this motor. Mm I think that is all I have for now

 

[oldboat1]

On the pump diaphragm -- when they get hard/lose their flexibility they need replacement, even if not split or holed.

On the low speed needle -- the sleeve goes on the end, but believe there may be another piece/sleeve sandwiched between two needle washers, then the packing nut on the end (contacts the outermost washer to seal and to keep the shaft from shaking loose.)

OR There might in fact be four washers between the threaded sleeve and the packing nut — and perhaps a larger plastic washer just inboard of the nut. (Think you will need a parts diagram.) It might be useful, though, to open up the domed compression washer on the carb top to see that the needle point in fact seats in the opening (test fit the needle). You would partially screw the needle into the end sleeve before inserting the needle into the carb and fitting it in place.

Only starting and idling is affected — no effect above idle speeds.

 

[hgxsilver]

I've heard that a sign of a leaking head gasket can be a clean plug. After the other day out getting that shudder or sneeze feeling, I checked the plugs. One was wet the other was dry and tan colored. There also looks to be a white crystallization around the head which is probably salt. Odd this is only happening now after all the running I've done over the past year trying to get the darn thing working.

 

[Tim Frank]

The spec'd plug is currently J8C....looked it up for a friend last week.

 

[hgxsilver]

Really? Is that not considered a very hot plug? What could this do performance wise good or bad?

 

[oldboat1]

J8s are hotter, as you say. Tim Frank gives good advice, but I think the plug for the RDS20 is J6C. There's an older UJ4J and maybe a UJ6J, and that might be shown as an alternate somewhere (I've never used them, so not sure whether either would make a difference in performance.)

 

[Tim Frank]

Hmmmmmm.....did a followup quick search. Four to two for the J6C.....then I stopped.

If the J6C are working for you just ignore my suggestion....
"Read" the plugs after you get everything sorted out and if you think you could use a hotter plug a jump from 6 to 8 is not unreasonable. It can epend on the use of the motor....i.e. long periods of trolling....

 

[hgxsilver]

I’ll keep the 6’s for now. Generally I’d be going faster than trolling speed. I’m dealing with a probably lean condition. One run was great the other was sneezing after warmed up. I’ll check the tune next time I’m out. The carb kit I got didn’t seem to contain the correct packing pieces for the needles so they are difficult to set. Thanks for the help. I’ll post my results this weekend.

 

[oldboat1]

I've heard that a sign of a leaking head gasket can be a clean plug. After the other day out getting that shudder or sneeze feeling, I checked the plugs. One was wet the other was dry and tan colored. There also looks to be a white crystallization around the head which is probably salt. Odd this is only happening now after all the running I've done over the past year trying to get the darn thing working.

not quite sure what you might be seeing there, but could retorque the headbolts (or go ahead and replace the gasket, cleaning out cooling passages while you are at it.) The t.stat gasket could also be the culprit, so might take a look at that.

 

[hgxsilver]

not quite sure what you might be seeing there, but could retorque the headbolts (or go ahead and replace the gasket, cleaning out cooling passages while you are at it.) The t.stat gasket could also be the culprit, so might take a look at that.

Interestingly enough, I was checking to see if I could crack the bolts of the head in preparation for the gasket replacement, (as my last disassembly resulted in many snapped bolts) a few of the head bolts were very loose. Friday It'll get another test run and Ill find out if that was the culprit. I may do it anyway as it is an oldie.

 

[Tim Frank]

Post #7 suggested a compression test. Have you done that?