2005 25hp Mariner Impeller change

blackers_92 · 25 October 2015, 06:53

Hi Guys

I recently purchased a 4.2 metre zodiac classic. It came with a 25 hp 2 stroke Mariner (2005) that starts fine however nothing is coming out of the tell tale. I checked the thermostat which is fine so I decided to check the impeller however I have been stuck trying to figure out how to drop the lower unit. I have found a few service manuals online however they all seem quite vague (i.e. showing it all connected, then disconnected)

I'd appreciate any advice / help

psycho · 25 October 2015, 08:10

If it is the thermostat type engine, then nothing will come out until it gets up to temperature, allowing the stat to operate. And then you will only get a dribble, compared to a powerful jet that you get on normal 2 strokes.

blackers_92 · 25 October 2015, 08:28

Thanks for the info psycho, did not know that!

Figured out how to drop the lower unit (had to pull the little pin all the way out of the shift shaft). The impeller is completely disintegrated though so I'll have to order a new one.

Should I be concerned that little fragments of the impeller could be throughout the engine? or should I just purchase a new water pump impeller kit install it?

Poly · 25 October 2015, 09:52

Blockers, yes it's certainly possible that some of the water passages are blocked with bits of impeller. There's not much you can do to reassure yourself about that without removing the head.

You could connect water or air to the telltale outlet (or anywhere else on the circuit) to try and blow / flush any debris backwards.

camelgas · 25 October 2015, 10:32

Connect a garden hose to the telltale, jury-rigged with jubbilee clamps etc.

As the lower leg is off you can back-wash safely, do it into a bucket so you can see what comes out.

Depending on how you get on with this, you may not have to take the powerhead off.

HTH.

dave3235 · 25 October 2015, 10:53

Hi all

I wonder whether you could weigh all the broken pieces and see if it's the similar weight as the new one.

uncle al · 25 October 2015, 19:14

remove your thermostat, and flush down through the thermostat hole with your hose,D ont do it at full water pressure though,put a bucket under the water pipe to see what if any bits come down. If you decide to take the power head of , before re-assembling refit the gear housing first make sure the water pick up pipe is in the correct position, if you have to jack the gear housing in with its mounting bolts/nuts, there is something not correctly up in the leg it should fit by hand pressure only.While you have the thermostat out test it to check that it is opening and closing. the temp is stamped on it , and don't use boiling water, heat the water gently, ideally using a thermometer to check the water temperature.

blackers_92 · 26 October 2015, 10:32

Thanks for all the responses so far guys!

I picked up a replacement kit for the impeller today, I reverse flushed the engine through the thermostat and tested the thermostat (worked fine) as per suggestions. There were a couple of tiny black specks in the bucket that collected the water that looked like grains of dirt, I am cautiously optimistic that this is a good sign asI anticipated something much more sinister! time will though, I still have it booked in for a service (just after Christmas though... that time of the year

)

I'll keep you all updated!

blackers_92 · 28 October 2015, 08:14

Hey guys went to change the impeller today and removed the gasket under the waterpump and noticed that there was a LOT of salt buildup and gunk underneath it especially on the fitting that surrounds the drive shaft.

I would ideally like to clean it before I cover it up again, any suggestions on what to use?

ALSO what direction should the impeller be bent in (i.e. left or right) the service manual states that the drive shaft spins clockwise therefore the impeller tips should sway to the left? Appreciate any clarification!!

blackers_92 · 28 October 2015, 08:43

one last thing the "insert" (part 8 above) is stuck inside the water pump assembly, I assume the o-ring sits in the gap between the two however the o-ring seems to be a smidge too large for it.

I assume the o-ring is sealing the entire water pump to the bottom gasket so I shouldn't be overly concerned about it lining the insert (part 8) perfectly?

Sorry about the constant questions, I'd rather be overly cautious and do it right the first time, perhaps someone else could use this as a guide too!

blackers_92 · 05 November 2015, 07:39

Just in case anyone was wondering everything went fine!

I took it out and it was all going fine (Forward, Neutral and Reverse) after a while it wouldn't shift into reverse. Turns out the shift washer was missing.

If anyone decides to use this in the future make sure you have your shift shaft washer in place, if you lose it a M6 stainless steel washer will suffice, its a bit fiddly to get in place another set of hands and some long tooth pliers help hold it in place.