Prop Locking Question (Reverse Locking Cam?)

[BB63QM]

I'm new, so bear with me. 1973 Thunderbolt 850; just purchased and rebuilt carbs and in boat electrical. She starts, but only on ether (suspect is weak spark due to old plug wires---solid copper replacements on order), but the prop does not seem to free up in Neutral as i would expect...its not engaged, but its not free either (as if the dogcam is disengaged, but not centering out, so its banging on the gears. Reverse Locking Cam: The prop rackets in forward as I understand is normal; in Neutral it moves in both directions but with an click click click every half rotation that you can hear and feel (like a bike derailer that is out of adjustment, but scaled up). If I move the shifter further back, the propeller frees up completely, when i expect that it is supposed to be fully locked to the drive shaft in both directions.

I read somewhere that the locking cam sometimes takes a little to engage, but no matter what I do (hand spin fast in either direction; raise, lower the motor in forward and in neutral, reverse spins free as opposed to being locked in both directions.

Please tell me that this is a stupid question, that there is an easy fix, and that I do not need to drop my L/U or replace anything major....I'm running on fumes after fixing all the problems I already found. fingers-crossed.

Thanks in advance.

 

[flyingscott]

Sounds like your cables are out of adjustment

 

[BB63QM]

Sounds like your cables are out of adjustment

That could be it, since neutral in the motor and prop does not agree with the remote on the other end of the cable. I'll reset the Neutral so that the handle is straight up rather than pulled back 10degrees. Maybe there is a relationship between the two cables I am not considering, in addition to the neutral cut-out switch. In doing so, is the a way to know where neutral is supposed to be on the motor slide?

Since I mentioned the NotNeutral kill-switch, there is an orange wire that connects to the stop position on my key. The orange wire goes nowhere in the official wiring diagram (i.e., it deadends at the motor harness). In reality, it continues into the motor [other motors have a kill switch]...should that orange wire be taped off, or tied to something (like one of the browns where the mercury-switch connects and (I think) grounds out the distributor when the motor is overly inclined.)

 

[BB63QM]

Ok...so I shifted the Remote to Neutral and disconnected the shift (lower) cable from the slide. Manually moving the shift lever, I can feel where FWD ends and neutral begins (about 2.5-3" before the end of the slide, as it takes some pressure to get over that leaving you at 2-2.5" about the 'hump'). At that point however, it doesn't feel like there is anywhere to go...the slide feels like it is pushing up against a spring (I cannot push the slide to the end by hand, but figure that I must have when it was connected, because then I managed to get it to where the prop spin free, and I can't do that by hand) and the prop is clicking in both directions. Could it be that the linkage from the slide to the lever is bent or off. I notice that if I run the throttle all the way forward, the level stops when its connector nut collides with the bottom of the lower carb, but there is a TON of play in the forward direction before that happens, so i don't see that being a problem.

 

[brodmann]

Your motor only running on starter fluid is not an ignition problem, it's a carburetor problem. Specifically a lack of fuel to the cylinders. Your neutral start switch might be in the control box. If not, google some information on the motor and I'm sure you'll find answers to most of your questions. Disconnect the cable, put the motor in neutral, where the propeller spins freely, put the controller in neutral and adjust the cable as needed and reconnect. Again, if your motor runs on ether, then your ignition system is working correctly. You need to work on fuel delivery, not get better plug wires.

 

[BB63QM]

Thanks Brodman. The motor runs well and for a prolonged test period once started (long after the ether is gone), and posts elsewhere mentioned that week spark and/or the lower unit not truly being in neutral might be the issue.

As mentioned in my last post, I cannot manually get the slide to a position where the prop spins free…the last 1-1.5 of slide are like pushing against a a heavy spring or somthing that is preventing movement elsewhere in the linkage. So I can’t do as you say.

 

[BB63QM]

See photos. The first is the shifter hitting the carb. Second shifter at the fwd point. The next is the slide position if I manually push the shifter back until the prop stops click and spins free. And the 4th is where the slide snaps back to as soon as the pressure is off (returning the clunking with otherwise free spin)

 

[BB63QM]

Ok. So I removed the linkage to the shift slide, thereby allowing the shift arm to pass under the carb bowl. It slipped right passed the SHOT to the far side under the force of a spring. I was able to pull it back to the port side, but now I can’t feel any gear shifting at all and their is a slight lift ability on the shift level that I don’t think was there previously.

Ideas?

 

[BB63QM]

No, moved the shift level back and forth several time and Clunk, it found reverse, I pulled it back and it went into reverse again (ie, prop is locked in both directions with about 40 def free movement). But now it seems to be stuck there.

 

[racerone]

Prop mut be turned when shifting to reverse.

 

[BB63QM]

Well that explains how it got into reverse (I had one hand on the prop and one on the lever. The question now is how can I get it OUT of reverse.

 

[jimmbo]

Just move the Linkage to Neutral, the Clutch Dog is attached to a Spring Loaded Shaft that will push it out of Reverse

 

[BB63QM]

Trying to push it out of gear is like pushing a wall…not springy like when I was push into reverse without rotating. The prop is locked in one direct and turns the shaft in the other. I don’t want to break anything, so if there is a trick in this direction too, let me know before I lean into it.

 

[jimmbo]

Trying to push it out of gear is like pushing a wall…not springy like when I was push into reverse without rotating. The prop is locked in one direct and turns the shaft in the other. I don’t want to break anything, so if there is a trick in this direction too, let me know before I lean into it.

It will only turn a bit more before is locks again in Reverse. The Linkage is just backing off of the Pin/Shaft that is connected to the Clutch Dog.

 

[BB63QM]

I don’t understand that reply…should I try to push it out of reverse even though it doesn’t feel like it’s going? I’m concerned because it seems that I am where I am because I trying to get it into reverse without prop rotation.

I don’t want to break/bend anything, as parts for this motor are hard to find and expensive when found.

 

[jimmbo]

When the Gear Case is in Reverse, the Clutch Dog Teeth are in a Channel, and the Propshaft has many Degrees of Arc, before the Teeth contact the ends of the Channel and stop. Forward Gear is a different Design, that has Ramps and allows full rotation in one direction, making the Clacking sound.

 

[BB63QM]

I see; you are responding to my comment about the shaft being locked with only ~40deg of free movement. (I put that in to confirm that the prop is indeed in reverse)

My primary concern right now is that I cannot get the clutch dog to back out, so the LU can re-enter neutral. What I’m looking for is either a process for accomplishing that, or confirmation that the solution is to drain and drop the LU and looking at the reverse locking cam and/or the clutch dog for damage (or anything else that I may be overlooking).

 

[jimmbo]

The Clutch Dog is pushed towards Neutral-Forward by a Spring inside the Propshaft. Did you have the Gearcase off Prior to this no shifting issue?

 

[BB63QM]

The Clutch Dog is pushed towards Neutral-Forward by a Spring inside the Propshaft. Did you have the Gearcase off Prior to this no shifting issue?

No. I was working on a starting issue and trying to eliminate obstacles to a clean start (one being drag from the prop not spinning completely free in neutral). In doing so, I realized that the only time the prop spun free was when the remote registered full reverse (ie, the was no reverse happening)…everything else is above in the thread.

 

[BB63QM]

The unit was only shifting between forward and what didn’t feel like a free spinning reverse. So I was exercising the upper shift lever directly (no linkage or cables) and turning the prop by hand to check lock status (I later found out that turn the prop was critical to shifting to reverse). Anyway, it popped into reverse, and then I was able to take it on and out a couple times. But now, it it locked in reverse.

Going in and when shifting other gears, you could feel the “hump” between gears; now it just feels solid…no give. In one directing, the crankshaft is fully engaged and in the other the prop is blocked after about 40 degrees rotation. If turning in that direction and putting forward pressure on the shifter, the prop occasionally will slip past the block.

Any advice on how to coax her out without wrecking something?
-keep trying by hand
-fire her up on the muffs
-(god forbid) drop the LU and look for damaged cams
-something else (forward pressure of x and back pressure on y, fairy dust, whatever…I’m at a loss).