Pee streambfits and starts

[mattswan2512]

Okay so fired the old girl up first yime since november and altho too a while to fire she now fires first pull. But the pee stream took ages to flow and when it does its fits and starts so surges then little then surges. .

Is this a new impeller ya reckon or something more?

[Andy B]

Muffs or in a tub?

I find if i haven't used my muffs in a while they go hard and don't form a very good seal around the water intakes. (especially at this time of year, cold!)
The answer is to drop your Muffs into a bowl of warm water for a while to soften them up.

If it's in a tub then either there's not enough water or yes it's time for a new impeller.

Again, it may be down to the rubber impeller being hard when cold.
Unfortunately this tends to end in them having a RUD. (Rapid Unscheduled Disassembly!)

It's good practice to start the year with a service and a new impeller anyway....

[mattswan2512]

Yes i was going to service her and yes tub andy.....i fitted new plugs the back end of last year and compression tested her just had that issue with the carb and tank flush last year.

Never serviced a 2 stroke so im guessing its a simple task of visual inspection check nuts bolts etc...clean fuel filter....drain oil from the leg and check for water ingress drop leg replace impeller ensuring not to turn the gear linkage rod put back together and add new oil and rubber seals jobs a jobben...

[The Gurnard]

Hi Matt ..just a quick note to say my 25HP mariner 2 stoke is similar to yours in description. It has a thermostat which controls the temperature. When first started and its cold ..it hardly spurts at all..then as it heats up a bit the thermostat lets the water pee out until it cools too much so shuts it off again. Once its been running a few moments it starts an even pee flow. Your 15HP mariner with also have a thermostat. Its worth taking its cover off and checking it as they often go a green colour with corrosion and can stick a bit.

Last year my Mariner didn't pump at all and I wore out a brand new impeller as I didn't have enough water above the impeller pump..thinking it would auto prime as it had every other year. This year its fine as I got a bigger bucket.

If you drop the leg on your Mariner..there is a small washer on the shift rod inside the top case. Watch for it and put it back in the same location on the shift rod or you loose reverse.. if you do loose reverse..you know its it the wrong place.

Just some things to consider that may assist. I'm no OB expert though

[mattswan2512]

Ho donny yes thanks for the tips there. I knew it would not come immediately due to tye thermostat but when it comes it floods fast then dribbles and floods and dribbles so i dont know if the impellar has a few less arms lol. I have not checked the thermostats.....might be worth a looksie and this washer do you mean the retaining clip for the gear rod linkage attached to the tiller?

Also donny whilst i remember did u fit a new gastket for the thermostat housing or just use the old 1 again?

[The Gurnard]

Nope..below the retaining clip..there is a rubber seal where the rod goes through the housing. On the rod.. and I cant remember if the washer is above or below the rubber seal..but it sits where the rod is "crimped" so cant slide right down the length of the rod..if that makes sense. I put it on the wrong side once and couldn't get reverse gear on the tiller control. I sctatched my head wondering why until I realised its this washer that was causing the problem

Hope that helps..if in doubt I will look my OB out and try to photo it..but now you are aware of it..it should be obvious.

[The Gurnard]

The thermostat gasket tore the last time I took it off ..it was reused several times. I guess its just luck. I made a temp gasket out of a bit of PVC when it tore ... meaning to replace it but it worked that well I have never replaced the PVC one. Beware the bolts can break..so its worth removing them every year and re greasing them again to avoid them corroding in

I had a post somewhere about breaking the bolts and drilling them out..but cant remember where ?

Edit..heres the post link

http://f-ribsandsibs.com/viewtopic.php?f=11&t=1600

[Andy B]

I think Donny beat me too it, when you run it in a tub make sure that the whole gearbox is submerged, not just the water intakes.
It's also a good idea to let it stand in the water for a short while before starting the engine to allow the impeller housing to fill with water so that there's no air around the impeller.

Muffs get around this problem due to the water pressure from the hose forcing water up into the water pump housing.

Water should come out of the pee tube from cold, it'll start coming out of the exhaust port when the thermostat opens.

[mattswan2512]

Thanks guys.
I have it in a large bin and its fully submerged so not the issue. I shall look to replace the impeller and the thermostat. Minor money and a feel good factor to boot

[rogerblack]

If you have the same Mercury 15HP 2 stroke as I have, this is from the manual:

14. Check for a steady stream of water flowing out of the water pump indicator hole.
NOTE: Engines equipped with a thermostat ‑ The amount of water flow can vary due to the thermostat operation.
It may take several minutes for the engine to warm up enough for water to start spraying out of the indicator hole.

But obviously still worth checking/replacing the impeller if it hasn't been done recently, and the stat if any doubt over it's operation. Better safe than sorry!