Trouble with Yamaha 150 outboard

Rusty5387

New member
I was out today fishing with the family and while heading home I hit a shallow area in the bay. I was running about 28mph and when we hit the shallow area we obviously slowed down and it pushed my outboard up as if I was trimming it up. The motor never shutoff and seemed to run fine during this whole process. Once clear of the shallow area the boat got back on plane just fine and ran home perfectly. When pulling into my marina I went to reverse into my slip but the motor would not shift into reverse. I tried multiple times and all it would do is rev up real high but no reverse. I could shift into forward and neutral with no issues. I tried doing a google search and have read anything from needing to replace the lower unit to it could just need a new hub inside the prop. I know I most likely need to have a mechanic check it out but was hoping someone on here may have some information for me as to what it could be. The motor is a 1993 Yamaha 150hp. I appreciate any help
 
Hub not likely because yuo can go fwd but that can be checked with motor not running. Shift gears and spin prop by hand. Figure out if gear is shifting but prop spinning.

remove cowling and see whats happening when you shift. try to shift from there.
Get a sense of if it is shifting but not working or not really getting from N to R.

The linkage might have slipped or the rod down to the lower unit bent?

Another step would be drop lower unit and see if you can shift it.
 
Just an update. I went down to the boat today only had about 20min to check it out before work. The motor started up and ran fine and shifted into forward with no issues. I had the cowling of so I could watch the shift cables work. When I shift into reverse the cable moves as it should but most of the time it will not shift into reverse. I say most of the time because it did shift into reverse 3 times when I was trying today. The mechanic at my marina won't be able to take a look until later this week.
 
You did not say what year Yamaha. I know some of the older ones had shift shaft issues. Hopefully not your case, because fwd works.
 
Okay another update. My father in law is a mechanic so he came down to the boat to see if he could figure it out. While at the boat it appeared the shift cable was not going all the way back into reverse so I helped and pushed it by hand and it shifted into reverse. After that it shifted into reverse everytime we tried. So we decided to go out for a quick cruise and while out I slowed down and went into neutral and when I went to get going again it wouldn't shift into forward. After multiple attempts of just going back and forth with the shifter it went into forward again and we went on our way. When pulling up to the dock I tried putting it in reverse and the motor rpm's went up real high and then it kind of slammed into reverse. I think it may be time for a new lower unit but I want to be sure before I purchase one. last thing I need is to order one and install it and find out it was the cables that went bad. Thanks for all the advice everyone I really appreciate it!
 
is the shift cable making full travel? Pull the cable loose on the engine end and see if it has any slop in it. If the cables have any age, go ahead and replace them.
 
Sound more like cables & linkage than your lower unit. Disconnect the cables and shift it by hand, that will eliminate half of the potential issues. If it won't shift (while running) then it may be the lower or the shaft but before I bought anything my next step (as other have suggested) is to simply drop the foot & check if it shift ok then, it's the only way to be positive it's in the gearbox.

Simple things first though, since it does shift, and the throttle is also part of the shifter I'd look there first.
 
Okay another update. My father in law is a mechanic so he came down to the boat to see if he could figure it out. While at the boat it appeared the shift cable was not going all the way back into reverse so I helped and pushed it by hand and it shifted into reverse. After that it shifted into reverse everytime we tried. So we decided to go out for a quick cruise and while out I slowed down and went into neutral and when I went to get going again it wouldn't shift into forward. After multiple attempts of just going back and forth with the shifter it went into forward again and we went on our way. When pulling up to the dock I tried putting it in reverse and the motor rpm's went up real high and then it kind of slammed into reverse. I think it may be time for a new lower unit but I want to be sure before I purchase one. last thing I need is to order one and install it and find out it was the cables that went bad. Thanks for all the advice everyone I really appreciate it!

Test like this...
Cowling off, disconnect the shift cable at the motor.
boat in water(securely tied to dock) or motor on earmuffs(keep clear of prop!!!), running at idle, manually shift from N to R to N to F to N at the motor. If it does that with no chatter, no slipping and banging, then your lower unit is OK. You have play in your cable or the linkage.

Connect cable and try to determine if it is returning to the same place each time you shift. Could be cable or connection at motor or in binnacle.
 
Update

The motor has continued to shift fin with only slipping once or twice on the past few trips. After everything I've seen and checked I believe it is not my cables. I think when I ran across that sandbar and abruptly stopped that it may have broken part of the gears. Now when I'm in forward there is a loud knocking sound so I'm going to have to replace the lower unit. Thanks for the help everyone
 
Okay so the lower unit finally blew up. It happened back in July and sounded like the gears just exploded inside. I'm just able to work on it now and hoping to get back out fishing asap. So now I have been looking for a lower unit to replace this one and it seems they are hard to find unless I want to spend a lot of money. I found a 2004 lower unit off a 150hp Yamaha. Does anyone know if this lower will fit my motor?
 
I have a good lower unit and several props

Hello Sorry to hear about your Yamaha I have a parts engine 115 HP (2 stroke) That should be the same as 150 HP. I purchased boat with bad power head and repowered. The bad engine had the lower unit serviced and repaired at locale marinia before the guy ran engine out of oil.. Unit is good have a few props (Turbo stainless and aluminuim also). Will sell cheap to member on this site. (I'm running inboard on my V-20) Hope that helps...Trans Yank
 
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