Shifting Problems Merc 150

[Cmthrush33]

I have a 1989 Mercury 150 that will shift into forward and reverse smoothly when ran out of water. Once it is in the water it shifts perfect in reverse, but when I shift into forward gear it seems like it does not want to engage right away, the boat will start to jump until it finally catches. Once it gets into forward gear it it runs like a champ, but it is trying to get it into gear that is the issue. Could someone please tell me whether this is a cable problem or a lower unit problem or etc.? I took it to my mechanic to fix it, he said it was the cables and that I needed to swiftly put it in gear but when I got it back it still had the same problem.

 

[j_martin]

Re: Shifting Problems Merc 150

I have a 1989 Mercury 150 that will shift into forward and reverse smoothly when ran out of water. Once it is in the water it shifts perfect in reverse, but when I shift into forward gear it seems like it does not want to engage right away, the boat will start to jump until it finally catches. Once it gets into forward gear it it runs like a champ, but it is trying to get it into gear that is the issue. Could someone please tell me whether this is a cable problem or a lower unit problem or etc.? I took it to my mechanic to fix it, he said it was the cables and that I needed to swiftly put it in gear but when I got it back it still had the same problem.

Adjust the cable by the book, and if it still acts up, the dog clutch is bad.

Most of the time what gets the clutch is slow shifting, letting it chatter slowly into gear. Idle speed needs to be below 1000, preferably around 700, and shifting into gear should be a quick clunk.

hope it helps
John

 

[CharlieB]

Re: Shifting Problems Merc 150

On the trailer, motor OFF, pull the lanyard.

While you watch the shift lever at the motor have a helper shift into Forward gear.

With a fine felt pen or suitable marker, make a reference mark on the linkage indicating EXACTLY how far the lever moved.

Disconnect the cable and shift manually into Forward, compare with your mark.

If the shifter has moved even the SLIGHTEST more manually then it did on the cable then the cable is stretched an in need of replacement.

 

[Cmthrush33]

Re: Shifting Problems Merc 150

The cables are adjusted properly was told that its probably the dog clutch how hard of a repair would this be to do? and what would the possible cost be for parts?

 

[sschefer]

Re: Shifting Problems Merc 150

Charlie and I think a little alike.. Here's how I would go about it.

At the engine end of the cable, look at the rack where the cable end lays in and connects the the shift rod arm. Remove the spark plug wires. Disconnect the shift cable at the engine and manaully shift the engine into neutral. Verifiy by turning the prop that the engine is in neutral (this is why you disco'd the plug wires, safety first).

There is a F-N-R cast into the shift cable rack. Make sure the pointer is aligned with the N when the lower unit is in the neutral position. If it is, then your mechanic probably already did this and it is probably a bad dog clutch.

If it isn't, with the engine in neutral, drop the lower unit far enough so that you can re-align the shift rod splines 1 spline in the direction is all it needs to go. It's not going to be off by more than one spline. It can be easier if you have a helper to watch the pointer while you align the rod. When it's good, bolt it back up. Then put the plug wires back on, put it on the hose, fire it up and check for proper shifting.

If the problem persists and a re-alignment was needed, then the dogs on the dog clutch are probably badly worn due to running it while it was misaligned. They have finally worn to point where they don't hold anymore.

The cost of repairs can vary widely but you can start at around 400.00 if everything else is still in good shape. It is sometimes more practical to replace the entire L/U with a fresh rebuit one for between 750.00 - 1275.00. Your mechanic may have a used one for much less or you might try your luck on eBay.

 

[CharlieB]

Re: Shifting Problems Merc 150

A worn/stretched shift cable will not pull the shift linkage that last 1/16 inch necessary to lock into Forward gear with a load on the prop in the water yet WILL seem to shift fine while running on the garden hose.

With the engine OFF and the Lanyard pulled or the spark plug wires disconnected, shift into Forward gear then STEP on the backside of the prop blade to turn the prop backwards, if it ratchets then it is not locked into gear. If it locks into gear then you should be able to turn the motor over backwards. Don't turn it much, this is just to test that it locks or not, turning backwards is NOT recommended for the water pump impeller.

Now, if it did NOT lock, shift back to Neutral, disconnect the shift cable and MANUALLY move the shift linkage to Forward gear, repeat the prop step test to see if it now locks into gear. If it now locks in then the shift cable is stretched and needs to be replaced before you continue to wear the corners off the shift dogs, then you will need to replace the shift slide and Forward gear.