Everyone please do me a quick favor!

[tipitina]

Anyone out there with an older Merc, will you please do me a huge favor? While sitting right where it is, will you place the motor in forward gear, and see if you can turn the prop? Mine won't go backwards, but will turn forward and make a clicking sound. Anyone else?

 

[Laddies]

Re: Everyone please do me a quick favor!

A prop will rachet clockwise ih fwd or c/clockwise in rev

 

[Clams Canino]

Re: Everyone please do me a quick favor!

Normal<br /><br />-W

 

[tipitina]

Re: Everyone please do me a quick favor!

Really? I thought when the motor is in gear, it shouldn't turn at all. When I put it in reverse, it will not move, it is locked in about a 4 inch span if you will. But in forward it is locked (wont go backwards) but will spin forward and make a ratcheting sound, I thought this might mean a broken gear tooth or something. Trying to find out why my engine stalls and dies when I put it into gear.

 

[rodbolt]

Re: Everyone please do me a quick favor!

the gearcase is acting normal. the dog is ramped and spring loaded. will ratchet if turned backwards when in fowd. the reverse dogs are not ramped and wont ratchet. you have other problems. time for a compression test and spark test.

 

[tipitina]

Re: Everyone please do me a quick favor!

But it is rathcheting when turned forward not backward....

 

[Crappie_Fan]

Re: Everyone please do me a quick favor!

You might check your linkage and make sure its adjusted properly. But if when your in the water and it goes into fwd gear and pushes you along, without any sudden high ramps of RPM, causing you to push it back into gear to make it stop (which is not good) then I would say your problem lies somewhere else not in the gearcase. Just my opinion of the situation.<br /><br />Good Luck

 

[Laddies]

Re: Everyone please do me a quick favor!

Some of the older units had a none racheting reverse, they had a habit of twisting the upper shift shaft when shifted without the engine running so later production engines have a racheting reverse gear also---Bob the reason it ratacts when you turn it forward its overspining the rachet and thats the way the clutch dog powers thr prop

 

[tipitina]

Re: Everyone please do me a quick favor!

Ok, here's the thing, last season I hit a rock right near the dock, so I was idleing, drifted into it, and it shut the motor off. Worked okay for the rest of that one hour trip, but the next week I took it out, it ran for about 5 minutes, right to the middle of the lake, and I couldn't get it to go forward at all. It would idle okay, but when I put it in gear it would just stall much like popping the clutch on a truck. This made me think lower unit. I did the little prop thing, it ratcheted, so I dropped the lower unit, but can't get in to the gears, and I'm wondering if I should still try.....Thanks for opinions, as I am lost!

 

[achris]

Re: Everyone please do me a quick favor!

Sounds very much like you've destroyed the top box. Very common with the older drives. The top gear set is weaker than the newer ones. As the engine died (when you hit the rock) it kicks back, like on the last compression. But with load on the prop (the rock) the top gearset took a hit in the reverse direction to the way they were designed to take load. That put a hairline crack in the base of one of the gear teeth. It usually takes a few hours running for the tooth to break off. Guess you got lucky and had it break in an hour. Easy check, drain the oil and take the top off the top of the drive. See any broken gear teeth? I thought so. Let us know what you find.<br /><br />Chris..........<br /><br />P.S. Your lower gearbox is performing as per design.<br /><br />P.P.S. You should be posting in I/O troubles, not the outboard forum.

 

[tipitina]

Re: Everyone please do me a quick favor!

Top box?<br /><br />It is an outboard....I can't figure out how to get into the lower unit any further without special tools....What is the top box? Does that apply to my motor?<br /><br />P.S. Still confused....

 

[achris]

Re: Everyone please do me a quick favor!

Sorry Tippy,<br /><br />I'm having a blonde moment. I thought you were talking about a Mercruiser. Ignore everything I said, most people do anyway. <br /><br />Chris.......

 

[Motor Boater Bill]

Re: Everyone please do me a quick favor!

Now that we have all agreed that the ratcheting is normal, how do the gears feel when you turn the drive shaft back and forth with the LU off, and turning the drive shaft far enough for a full revolution of the prop shaft in forward and reverse--smooth? No excess play? Does it shift OK? Or does it grind, or stick or "skip" in places? If it feels really good, then the LU may be OK. Next step would be to put it back together, fill a trash can with water, and try it out. Your problem of stalling could be in the powerhead or the carbs. Take it one step at a time.<br /><br />IF it is ratcheting when the shift is in forward and the prop is turned forward, you may have broken the teeth on the clutch dog. But if it only ratchets one way and not the other, the way it is ratcheting is probably backwards. Look at the prop VERY carefully to figure this out.<br /><br />If you put the LU in reverse with the LU off and you can't turn the prop (which should then turn the drive shaft) you have a problem with the gears and will need to tear down or replace the LU. Same if you can't turn the drive shaft with the LU in gear, which should turn the prop shaft. Do these simple tests and tell us what it is doing.

 

[tipitina]

Re: Everyone please do me a quick favor!

The prop shaft is SLIGHTLY bent, and the mechanic says it sounds like a broken rod or compression.......how can i check this?

 

[Motor Boater Bill]

Re: Everyone please do me a quick favor!

If you had a broken rod the motor would not run.<br /><br />Check compression with a compression tester, about $10-15 at Sears or auto parts store.<br /><br />How did you determine the prop shaft is bent--did you take the LU apart or just check it for run-out as it turns? <br /><br />Did the mechanic see or hear your engine or did you just talk to him about it?

 

[tipitina]

Re: Everyone please do me a quick favor!

A new mechanic just opened up on my way to work (near the lake) so I grabbed my lower unit and stopped by on my way in yesterday. While spinning the prop shaft very slowly you can tell it is slightly bent. It is unnoticeable by just looking at it, but once it starts spinning I can tell just cause I am looking for it. Should I replace the unit because of this?<br />I just asked him what it might be if the lower unit is okay, and he said it may be a broken rod, or just bad spark, but it was hard to tell. He said he didn't work on the old mercs, because once you're in there you have to replace everything. He said he could take a quick look at it, but I want to go ahead and replace the water pump, before I put the LU back on. <br />I picked up a compression tester last night, and plan to check the compression today after work. How does one do this?

 

[tipitina]

Re: Everyone please do me a quick favor!

ok, compression tested good on all cylinders, does that mean I don't have a broken rod?<br />Should I replace the lower unit if the prop shaft is bent?

 

[Clams Canino]

Re: Everyone please do me a quick favor!

Assume your powerhead is FINE. Drop the lower unit off at a REPUTABLE shop and have them go through it and be done with it.<br /><br />-W

 

[Motor Boater Bill]

Re: Everyone please do me a quick favor!

Assuming that the mechanic you took the LU to is qualified (and this may not be the case) what was his assessment of its condition? It's hard to know what "slightly bent" means. We still don't know if the LU is the reason your motor dies when you put it in gear. Having the LU rebuilt by a shop may cost more than replacing it with a used one. I don't know this for sure, but it is a question I'd look into before having that done. But before doing either I'd want to know what the real problem is. Clams is a real expert on your motor, and his advice will be a big help to you in figuring out what's up with your motor. I'd just be wary of spending a lot of money on any repair before you have a real clear picture of what the problem is.

 

[tipitina]

Re: Everyone please do me a quick favor!

I also don't want to spend money not getting it fixed, especially since I need to redo the floor and transom. I don't want to begin doing this until I know the motor is running. The mechanic just said he didn't want to tear into the lower unit and charge me $65 an hour, since he could tell the prop shaft was bent. My thoughts are maybe the impact that bent the shaft messed up the prop somehow. I don't really have any idea. The compression came up as follows. Keep in mind the engine was cold, as I can't start it without the lower unit on....<br />Cylinder / Highest compression<br />1 / 68<br />2 / 72<br />3 / 70<br />4 / 76<br />5 / 80<br />6 / 80<br />I think the way the engine idled fine last time it was out, it must be something with LU or prop....