2hp outboard not peeing.

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dedwards

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Hi,

I've got a 2hp Mariner and am trying to diagnose why it gradually runs out of power over the space of about 10 mins. Its not peeing so I assume theres a cooling problem but I can't find anything wrong with it.

I've taken the gearbox off and checked the following:

Impeller in good condition and turns when I turn the prop.
Impellor housing is clean.
The up tube and the rubber gromet that mates to it seem to both be in good condition.
I've used a straw to blow water up the up-tube and (when I turn the engine back the right way up) it comes out down the inside of the leg.
I've also blown water through the peehole and that also runs down the inside of the leg.

So, any ideas what i'm missing?
 
dedwards said:
Hi,

I've got a 2hp Mariner and am trying to diagnose why it gradually runs out of power over the space of about 10 mins. Its not peeing so I assume theres a cooling problem but I can't find anything wrong with it.

I've taken the gearbox off and checked the following:

Impeller in good condition and turns when I turn the prop.
Impellor housing is clean.
The up tube and the rubber gromet that mates to it seem to both be in good condition.
I've used a straw to blow water up the up-tube and (when I turn the engine back the right way up) it comes out down the inside of the leg.
I've also blown water through the peehole and that also runs down the inside of the leg.

So, any ideas what i'm missing?
Click to expand...
Water isnt cooling, the slowing down is probably it seizing due to overheating! Thats what they do. Probably need to take the head unit off the leg and check the pathways for the water arent blocked.
Stu
 
Could well be blocked cooling channels in the head and block. This happens quite a bit when small engines are used in saltwater and close to sandy beaches. The only way is to take the head off and machanically clean.
 
Mine was absolutely clogged with salt and corrosion and other muck when I finally got round to taking the head off and unblocking all the weeny channels and orifaces.Being a tightwad I reused the old head gasket.
 
But when I blow water up the pipe it seems to come out the other side leading me to believe the head isnt blocked. Is it possible that my problems can be caused by a partial blockage?
 
Ok from the start and a few people have previously covered as well. The loss of power is overheating, nothing to worry about on these little things, they are so agricultural, they will take a lot of abuse.

So to check the water ways, you need to remove the head, this is very simple and should only take an hour maximum including the clean out.

I'll describe it on here for the benefit of others. So;

1) Open Fuel tank cock. Remove engine Cowling, on Mariner and Mercury: remove top cover, spark plug cover from one side of the cowl and unscrew the two side cowlings. Tohatsu: remove the spark plug cover and Two side cowlings.

2) ensure the fuel tank cock is closed again (if full of fuel), remove the fuel feed line and unbolt the 2 bolts holding the fuel tank on.

3) Remove the HT lead and sparkplug from the cylinder head

4) undo the 4 bolts holding the cylinder head on, clean out the waterways and inspect the head gasket for delamination. If the head gasket is in a serviceable condition, with no burning, warping or disformity in the cylinder sealing ring, it is fine to reuse.

Note, the cylinder head bolts can be a real bugger if the engine is older and has not been taken apart regularly. Be VERY careful not to shear these bolts as you will have one hell of a job removing and retapping the head as it's very soft and cheap metal alloy.

5) rebuilding is reverse of stripping. Ensure the cylinder bore is clean and no salt chippings from cleaning the waterways in there, do not worry about any scoring in the bore, as said before these engines are very agricultural.
 
IMHO the peehole is a coolant indicator. You stated that it was not peeing the bulk of the coolant runs down the leg. It may be that the peehole is connected direcctly to the chamber at the top of the leg and if there is no blockage there water injected in the pee hole or leg may come out of the other opening. It does not automatically follow that water is circulating freely around the head.

I had no water out of the hole but the engine was running fine as the water was still going down the leg.
 
To clear the passageways you do not need to take it apart. Make up a solution of citric acid and then make up a rig to get it into the 'pee hole' (using a small funnel or tube should do the trick) and/or impeller inlet and that will dissolve the crud. Usually best to have engine laid out horizontal and work the solution in. You will know when you have cleared it as the liquid will flow through the circuit.Citric acid is a fairly benign acid so quite safe - it is of course in jam, coke etc. You could probably use coke (the drinking kind) anyway!
 
monkfish24 said:
Ok from the start and a few people have previously covered as well. The loss of power is overheating, nothing to worry about on these little things, they are so agricultural, they will take a lot of abuse.

So to check the water ways, you need to remove the head, this is very simple and should only take an hour maximum including the clean out.

I'll describe it on here for the benefit of others. So;

1) Open Fuel tank cock. Remove engine Cowling, on Mariner and Mercury: remove top cover, spark plug cover from one side of the cowl and unscrew the two side cowlings. Tohatsu: remove the spark plug cover and Two side cowlings.

2) ensure the fuel tank cock is closed again (if full of fuel), remove the fuel feed line and unbolt the 2 bolts holding the fuel tank on.

3) Remove the HT lead and sparkplug from the cylinder head

4) undo the 4 bolts holding the cylinder head on, clean out the waterways and inspect the head gasket for delamination. If the head gasket is in a serviceable condition, with no burning, warping or disformity in the cylinder sealing ring, it is fine to reuse.

Note, the cylinder head bolts can be a real bugger if the engine is older and has not been taken apart regularly. Be VERY careful not to shear these bolts as you will have one hell of a job removing and retapping the head as it's very soft and cheap metal alloy.

5) rebuilding is reverse of stripping. Ensure the cylinder bore is clean and no salt chippings from cleaning the waterways in there, do not worry about any scoring in the bore, as said before these engines are very agricultural.
Click to expand...


re 4) +1 work the bolts back and for' just a tiny bit of a turn at a time take plenty of time and plenty of plus gas , as you work it out a tiny bit at a time if they shear it a really hard job !
 
The head isn't where the major obstructions occur. Take the powerhead off the leg. There are channels which block up there, and the passage from this part of the block the block to the head is a bottleneck. I cleaned them out and reamed them a bit wider as well.
These channels are the only passage from the pump to the head and waterjacket, and back to the leg to the leg.

powwerheadgasketflange.jpg
 
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My Mariner 2M head doesn't look anything like your head but I agree it's more likely to be the source of the blockage. See the end of this pdf.
Also mine doesn't appear to have a 'pee' hole, just an exhaust relief hole partway down the leg which sprays a mist of cooling water.
 
congrats

Alahol2. In a spirit of research rather than necessity, I have been looking at your pdf, which seems to me to be an exemplary bit of clear and reassuring instruction.
 
'Lakey' is on the money with this one.

2hp Mariners (and their equivalents) have tiny water channels and I've had the powerhead and head off to find gooey salt deposits all but blocking the channels. (particularly where Lakesailor mentions - the tiny outlets from the powerhead into cylinder waterway)

The good news is that they're easy to dissemble so personally if I was having cooling issues, I'd pop the powerhead off and the cylinder head off and give the whole lot a damn good clean.
 
jsl said:
Alahol2. In a spirit of research rather than necessity, I have been looking at your pdf, which seems to me to be an exemplary bit of clear and reassuring instruction.
Click to expand...

+1.

I have downloaded a copy because the photos in it seem similar to my old Yamaha 2b. Later on this year I intend to take it apart because of a water (non)flow problem. Since if it is necessary to go on the tender I can always use the oars, the little Yam does not merit a high priority. Too much on my plate at the moment because the to-do list of my boat restoration project is continually expanding. Must be the heat. :(
 
So, slightly put off by the threats of sheared bolts I havent removed the head but I have taken the leg off as per alahol's pdf. There's a thin layer of brown scum in the channels but nothing major. I blew water down the 'out' hole and it came up both the 'in' holes so no sign of a blockage.

Reassembled and run but still no pee. On closer inspection the peehole does just go to the inside of the leg so maybe it is just an exhaust as previously mentioned. In any case, the only thing coming out of it is air.

Maybe this is how its supposed to be and i've already fixed the blockage. will give it a proper try at first opportunity.
 
oldgit said:
Mine was absolutely clogged with salt and corrosion and other muck when I finally got round to taking the head off and unblocking all the weeny channels and orifaces.Being a tightwad I reused the old head gasket.
Click to expand...

+1

Done this twice in total, once on the pontoon, to everybody's great amusement. About a cupful of crumbly salty deposits removed in total. Use thin wire to poke all the channels clean.
Be careful NOT to twist off any bolts in the dis-assembly process ;)


Ancient Yamaha 2b -almost identical...
 
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If its same as yam 2hp and i think it is
it will be the head probably
mine was totally blocked also you have to clean out the barrel
your citric juice wont work!
the head came off easy
do you have a feel for bolts?
also if a bore is scored badly thats not good for any engine!
as will result in low compression
id put money on head/barrel clogged with salt crud
are there 6 holes in leg?
lots of water should come out..it did on mine soon as i unblocked it
 
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