Evinrude 150hp lower unit removal

[jdlloyd_iboat]

I have a 1988 Evinrude 150hp which I have run for 2 seasons without a problem except for the replacement of a thermostat. I do not know the history of the impeller (water pressure has been good) but I am wanting to replace it this season. I am not too familiar with maintenance on outboards but am mechanically capable of performing the job, have a manual and the parts. My question relates to a fear of removing the bolts! I easily sheared a bolt off the water pump housing on this motor which indicated that those small bolts were fairly well corroded and had not been removed in some time. What should I be concerned about in removing the bolts on the lower unit? Can I exert a good deal of torque withut fear of shearing one of these bolts? Are these bolts pretty robust? Does it depend on length of time they have been in and if they were sealed with proper anti-seize? I eventually will need to replace the impeller; should I be pre-emptive or should I wait until it's absolutely necessary?[colour=null][colour=null][colour=null]

 

[iwombat]

Re: Evinrude 150hp lower unit removal

The answer is most of those bolts are pretty robust, but the one under the trim tab (I think you have that one) isn't too hard to snap out. A little heat can certainly help if they're really hard to remove. Best to go pretty easy on 'em all and use heat to try and free up any obstinate ones.

I'm all in favor of a pre-emptive impeller replacement. Others may disagree. I'm assuming when you refer to the "water pump housing" you're talking about the thermostat housing. The water pump = the impeller.

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

I erred in my earlier note. It's a 1990 Evinrude (not that it makes any difference as for my fear of bolt removal). Sorry for the error though.

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

The answer is most of those bolts are pretty robust, but the one under the trim tab (I think you have that one) isn't too hard to snap out. A little heat can certainly help if they're really hard to remove. Best to go pretty easy on 'em all and use heat to try and free up any obstinate ones.

I'm all in favor of a pre-emptive impeller replacement. Others may disagree. I'm assuming when you refer to the "water pump housing" you're talking about the thermostat housing. The water pump = the impeller.

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

Thanks,iwombat. You are correct it was the thermostat housing; influence from my auto engine experience is showing.

When you suggest heat to ease the removal, are you talking about propane torch type heat and are you talking about heating the bolt head or the overall general area of the bolt?

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

Thanks,iwombat. You are correct it was the thermostat housing; influence from my auto engine experience is showing.

When you suggest heat to ease the removal, are you talking about propane torch type heat and are you talking about heating the bolt head or the overall general area of the bolt?

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

Two weeks later and several cycles of heat and some torque and I have successfully removed all the lower unit bolts withour breaking any. The trim tab bolt was the toughest to get out. The unit has dropped about an inch and I suspect I have not released the shift linkage as I am supposed to do. I have read the forum and this seems to be a common hang-up. I have a Seloc manual and it isn't very explicit about this step. I have removed the shift cble linkage and the shift lever rocks back and forth as I raise and lower the unit. I believe I haven't really released the linkage as required. My engine has three carburetors and I see a 3/8 bolt head on the starboard side of the linkage bearing. Is this the bolt I need to remove? After its removal do I pull the shift mechanism through to the port side to disengage it from the vertical shift linkage? It looks like I have to remove the intake and maybe the bottommost carburetor to do this easily. Am I on the right track?

 

[mikesea]

Re: Evinrude 150hp lower unit removal

your right,that is the bolt that needs to come out,removing the engine cables from the linkages gives you more room,you dont need to remove the carb,bring the lower back up with a couple bolts,shift it into rev,which brings the shaft and bolt downward.I then use a 1/4 inch long extension,with a 3/8 flex head socket,wrap a piece of electrical tape around the knuckle of the socket,this prevents it from flip flopping around as you put it in place,after you can grab it with a long nose pliers or one of the different grabber type tools.Be careful with the waterpump screws(the real waterpuump screws ,LOL)they arent usually a problem,but if your doubtful,you can use some heat on the lower unit below where they sit,its wise to change the impeller once a year,if for no other reason then to excerise the bolts,especially in salt water.The whole shift shaft will come down.Dont spin it around,it has threads that determine length,the length is important,when putting it back up,you can usually grab the shift shaft with a pliers under the cowling pan,if you need to turn it one way or the other,I use grease or anti seize for next time on all bolts in the lower unit

 

[jdlloyd_iboat]

Re: Evinrude 150hp lower unit removal

While awaiting a reply I went ahead and removed all the stuff in front of the carburetors and removed the lower one. This made it real easy to get at the bolt that I really could not see before. I removed that 3/8 bolt and the lower unit dropped with no problem. I will know what to do next time and I might be able to do it without all the extra disassembly. I do not have a 1/4 inch drive set so I might need to get one of those. The bolts on the water pump were a litle seized but they eventually came out with some gentle persuasion. I am now ready to replace my pump. I feel like I could do this without any fear now and will certainly use the anti-seize on all the bolts like you suggest. The impeller was at least 3 years old as I have had the boat 2 seasons and didn't look too bad ( I really don't know what a bad one looks like) but I will breathe easier this season knowing I have a new one in there. Thanks for the advice. I hope the weather gets warmer he in No. VA so I can go bass fishing!