Mercury Thunderbolt 9.8 won`t **** water

[lupien]

Hey guys,

I have an old Mercury 110 9.8 Thunderbolt outboard (1980 maybe older, it as blue stickers). The water pump blew so I opened up the bottom part and replaced the water pump (was totaly gone) and I also had to replace that little PVC tube that the brass tube slides in because it was all melted. So now I assumed it would run fine but water still isn`t pissing. What should I do now? I`m good with mechanic but I have never did much on outboards (never breaks) so i would rather do it myself. I assume something is block higner up with peices of pump. Were should I look? Is there a thermostat in these engines that could have stayed stuck with a peice of rubber ? I read about water ducks can jam, how do I open those up to check if it is blocked?

Should I open this part ->

What is that plate anyways? Ive read I should remove the exhaust plates and water jacket cover to find the pieces but I don`t really know what is what.


Thanks alot. Sorry for the long post and all the questions.

Lucien

 

[diaric]

Re: Mercury Thunderbolt 9.8 won`t **** water

believe thats the cover to the exhaust manafold. didn't have your serial so this diagram might be different year. cylinder bloak/crankcase link shows it http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=13716

 

[mcdgary]

Re: Mercury Thunderbolt 9.8 won`t **** water

I had a 1969 (bought new) for many years. I replaced the water pump 2-3 times, or as needed. Dirt dawbers have a tendancy to plug up the **** hole; even a marine mechanic told me this. I used a 100 # test monofilament to ream out the hole quite often. A piece of wire will work also. As an example, at first when working the monofilament up the hole a little water would began to ooze out, continued working and voila - a good stream. Incidentally, I did not have a thermostat and neither do I have one on my 25 HP Merc.

 

[tashasdaddy]

Re: Mercury Thunderbolt 9.8 won`t **** water

i just this morning pull an impeller that had melted and clogged the water pump outlet, and part of the water tube, the cooled rubber was like rock.

 

[lupien]

Re: Mercury Thunderbolt 9.8 won`t **** water

Thanks alot guys!

So I checked everything I could. Opened up the lower unit, the pump is fine, tubes are not clogged all is good. I then opened the exaust plate, same deal, I cleaned all the water holes with weed wacker wire and no blockage. I used a compressor to blow air in the pee hole and the aire flows thrue everywhere. I also opened up the cylinder heads and ran a wire down the water duck there too. Air flowed with no problem in the top or bottom of the engine but not from one end to the other.

So I figured out the blockage is at the end of the copper tube where it meets the cylinder block and crankcase (powerhead i guess its called). So its now a much bigger job to get there. I assume I need to take out the entire block to see the end of that coppertube right? I think there is somekind of rubber fitting or grommet where the tube meets the engine and I think that peice might have melted.

Is there anything i need to know before I rip this thing appart? Will I need special tools like pullers or something? I`m pretty good in mechanical stuff so doing this on my own doesn`t scare me at all but I`m new to boat engines so this will be a first.

Thanks again!!

 

[Harker]

Re: Mercury Thunderbolt 9.8 won`t **** water

They are easy to take out..but I reccomend a manual be handy. You will need a new lower gasket where the powerhead sits on the mid section. You have to disconnect the tiller, gasline and kill switch..then remove the lower shield (3 screws) and 4 bolts holding the power head on. I'd get gaskets for the exaust jacket, intake covers and water jacket over the head and replace them while the powerhead is out. You will need a Torque wrench and manual for the tightening sequence and torque values. You can see all the passageways on the bottom of the powerhead and clean them up a bit.

 

[naspet]

Re: Mercury Thunderbolt 9.8 won`t **** water

Hello i have some problem to my mercury 9,8 ,the only difrences is ,if i blow water or air to water tube the only way out is from flushing hole .
So probably y should dismount the engine and for this i need a repair manual .
Does anybody have a manual for this type of engine .

Thanks

 

[bob1340]

Re: Mercury Thunderbolt 9.8 won`t **** water

Hey guys,

I opened up the bottom part and replaced the water pump (was totaly gone) and I also had to replace that little PVC tube that the brass tube slides in because it was all melted. So now I assumed it would run fine but water still isn`t pissing. What should I do now?
Lucien

Before you pull the powerhead to check for issues make sure your pump is actually pumping good. Remove the lower unit and stick it in a tub of water and spin it with a drill. Did you put a new seal in for the tube that goes to the powerhead? The plastic tube that was melted is not the seal, it's just a guide.