Impeller/Water pump 1988 Merc 135v6

[strippingguards]

I bought the boat/engine used 2 years ago and I have no idea about the age of the water pump and/or impeller. Is this something that the average handyman can repair in the yard?

 

[bill giffear]

Re: Impeller/Water pump 1988 Merc 135v6

Doug, I replace my water pump every 3 years whether it needs it or not,most water pump kits come with step by step instructions. Also Clymer Official Shop manuals are available thru this web site they go for about 25.00 bucks.Water pumps are pretty easy to do if you have the manual.<br /> good luck Bill

 

[strippingguards]

Re: Impeller/Water pump 1988 Merc 135v6

I do have the Clymer shop manual but I am hesitant to do anything that involves the lower unit. Do I need and special tools or equipment to detach the lower unit. My experience so far includes replacing the whole trim/tilt motor, minor electrical work, replaced propeller and changed the lower unit oil for winterization.<br />Are there any specific challenges about opening up the lower unit? The manual mentions a vise with pads or something? Is it just held on with some bolts - should I buy the water pump kit prior to tinkering with the lower unit - and where can I order such a kit for my motor? Thanks

 

[ehenry]

Re: Impeller/Water pump 1988 Merc 135v6

You don't need any special tools to replace the impeller. The vise with pads is to hold the lower unit while you're working on the water pump. An extra pair of hands work just as well. An impeller shouldn't run you about 20 to 30 bucks if that much. You shouldn't have any problem judging from what you say you've done. Just follow the instructions in the book.

 

[strippingguards]

Re: Impeller/Water pump 1988 Merc 135v6

Do I have to take the lower unit completely off to change the impeller?

 

[strippingguards]

Re: Impeller/Water pump 1988 Merc 135v6

 

[kenthrussell]

Re: Impeller/Water pump 1988 Merc 135v6

Hi yes you do have to remove the lower unit to replace the pump as the pump sits right on top of the lower unit

 

[tufftango]

Re: Impeller/Water pump 1988 Merc 135v6

The easiest way to replace the impeller is to remove the bolts holding the lower unit up. remember that there should be a small black cap on the top tailend of the lower unit that once removed will expose a 1/2" bolt that hold the ajustable fin on the back of the motor, once removed there will be another 9/16" bolt under it. Before removing, place the motor in netural, and do not move until installation is complete, I do not care what friends tell you, take it from someone who learned the hard way. Once the lower unit is down, follow your owners manuel info to replace the pump assembly, it's really easy. Don't just replace the impeller, for $30 you can rebuild the entire water pump and forget it for a few years. You will need a friend with a strong back to help lift the lower unit back up, and to turn the fly wheel until the shaft spline lines up. If you haven't moved the shift lever, you should have no problems with the gearing. Also do not be alarmed if you have parts in the rebuild kit that are left over, the kits are made for several motors. I have never changed the water pump on this motor, but have changed on many others including some mercurys, so some of the bolt sizes may be different. This job is way to easy to pay someone a couple hundred bucks to do it for you.<br />You will need a friend and about two hours to do it right the first time. Good luck, and happy boating.

 

[strippingguards]

Re: Impeller/Water pump 1988 Merc 135v6

Thanks<br />That was the kind of information I was looking for.<br />So if my overheat alarm is coming on with some frequency - I may be overheating due to a water pump/impeller problem - which should be changed every few years. Since I bought the boat without know last time of service - it should be done. I shouldn't pay hundreds of dollars for this simple job - I just need to get a buddy to help with the muscle.<br />Follow-up questions:<br />what is a true indicator that the water pump/impeller is the cause of my overheat alarm sounding? Water does spew out the telltale but it takes a while to get it flowing properly and it is very hot water.<br />What could be some other possible causes?<br />What could go wrong while disassembling the lower unit?<br />Are there any custom fit gaskets that are needed before re-assembling the lower unit?