Mariner 30hp 2 stroke - impeller change

paulbrown22 · 26 July 2015, 12:16

My first time trying to change the impeller on this engine, a 2000 vintage Mariner 30 2 stroke (carb).

The gear selector rod seems to be held together by a joint and dowel pins (parts 22 and 23 here: Mariner 30 HP (2 CYL.)(International) Drive Shaft Housing Parts).

Not sure where I've put my owner's handbook - whats the accepted method of separating the gear linkage on this engine so I can drop the gear casing?

Are you meant to try and drive out these little dowel pins, or disconnect the linkage in the cowling under the carb?

Thanks,

Paul

dave3235 · 26 July 2015, 14:23

Quote:

Originally Posted by paulbrown22

My first time trying to change the impeller on this engine, a 2000 vintage Mariner 30 2 stroke (carb).

The gear selector rod seems to be held together by a joint and dowel pins (parts 22 and 23 here: Mariner 30 HP (2 CYL.)(International) Drive Shaft Housing Parts).

Not sure where I've put my owner's handbook - whats the accepted method of separating the gear linkage on this engine so I can drop the gear casing?

Are you meant to try and drive out these little dowel pins, or disconnect the linkage in the cowling under the carb?

Thanks,

Paul

Hi Paul

This is the same as my 20hp undo the 10mm nut under the carb.All will become clear.Also double check for any washers on rod you don't seem to have one on the picture but check.

paulbrown22 · 26 July 2015, 19:28

Super, thanks Dave!

A shame I only just stripped and refitted the carb a few weeks back...

paulbrown22 · 08 August 2015, 21:50

Finally got round to doing this today, in between rebuilding the end of the boom for the sailing yacht!

Was a bit of a pain to get at, but with carb, starter motor and electrical panel all removed, I could finally undo the nut one flat at a time (as there's no space to actually move the spanner), disconnect the gear linkage and drop the leg… (the same nut was also a right pain to get back on again - no room to manoeuvre).

The existing impeller seemed fine, but having taken it all apart and not knowing it's age, fitted a new one anyway.

Sadly whilst the engine starts and idles beautifully after the carb clean, still not pumping any water (despite being fine a few weeks ago!). I did blow through it with an airline while all apart, and all the passages seemed clear. Will have to work through everything again - given it's very low usage (has been owned by us from new), hopefully nothing serious!

yam man · 08 August 2015, 22:24

U sure u lined the water tube up Paul

dave3235 · 09 August 2015, 00:26

Quote:

Originally Posted by yam man

U sure u lined the water tube up Paul

Hi all

Have a look at the parts print out there seems to be a locating clip and nut 42 and 41 if not done already .

paulbrown22 · 09 August 2015, 22:53

Is there any trick to lining it up or checking it Graham? I must admit, I didn't explicitly check it, as I kind of assumed if the gear selector and drive shaft all lined up, then surely the water pickup was lined up as well! I shall disassemble and check next weekend… The woodruff key was definitely in as well, but I will double check it is doing it's job and the impeller is spinning properly if it's all coming apart again. This is all much easier on my little 6hp Johnson!

Hmmm, I don't think I touched the retaining clip/nut as I only dropped the gear box and didn't touch the water pipe going down the leg, but shall definitely double check it!

dave3235 · 09 August 2015, 23:39

Quote:

Originally Posted by paulbrown22

Is there any trick to lining it up or checking it Graham? I must admit, I didn't explicitly check it, as I kind of assumed if the gear selector and drive shaft all lined up, then surely the water pickup was lined up as well! I shall disassemble and check next weekend… The woodruff key was definitely in as well, but I will double check it is doing it's job and the impeller is spinning properly if it's all coming apart again. This is all much easier on my little 6hp Johnson!

Hmmm, I don't think I touched the retaining clip/nut as I only dropped the gear box and didn't touch the water pipe going down the leg, but shall definitely double check it!

Yes Dave !

dave3235 · 13 August 2015, 02:11

Quote:

Originally Posted by dave3235

Yes Dave !

Keep us posted

paulbrown22 · 13 August 2015, 08:40

Will do - sadly I'm in London this week, but hoping to be back with the engine at the weekend and should then have some time to try again!

mattwarner · 13 August 2015, 09:07

I had exactly the same on my 25hp Merc, I was running it in a cement bucket but it wouldn't pump any water, I swapped for an old water butt and filled with water and it pumped water fine.

Might we worth a try? Also have you tried cleaning out the thermostat (if it has one) or remove completely just to eliminate this.

paulbrown22 · 13 August 2015, 14:28

I've been running it on muffs for years to clean through, always running perfectly and pumping water instantly. This is the first time it hasn't pumped any water, and I hadn't really done anything - it was fine one weekend after cleaning the carb and putting it back on, I put the boat back in the garage, pulled it out the next weekend, and no water pumping anymore... Was tempted to try it in a barrel or something, but not sure why the muffs would have suddenly stopped working.

Yep, I opened up the stat and that was perfectly clean.

paulbrown22 · 15 August 2015, 18:21

I took it all apart again, checked impeller alignment and the woodruff key, tested pump manually by turning it as fast as I could and it seemed okay - water came out. Carefully reassembled to ensure the water tube went into the top of the pump housing, put everything else back together and started the engine on muffs - no water…

Now filling a barrel to test in just in case it's become upset with my muffs!

paulbrown22 · 15 August 2015, 19:11

It clearly has become upset with running on muffs!

Running in a barrel and it started pumping instantly and strongly just as it always used to… So probably was fine after the last strip down, but it's now all been checked again. Which was partly a good thing, as I previously hadn't put the ball bearing back in the gear shift mechanism that helps locate neutral/forward/reverse!

Thanks for all the help and advice!