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Help wanted please had a bad day

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ktmjunkie

Contributing Member
"Hi all I have a 4cyl 2stroke

"Hi all I have a 4cyl 2stroke 50hp still not sure of the year ser no 9282468 blueband.
fitted new impeller,lifted motor from top, checked top seal on water tube, connected hose to bottom of tube water runs through pee tube.blow through pee tube sounds clear when reassembled started motor and no flow through pee tube unless engine is at max revs nothing on tick over. can anyone tell me what to do next.
Regards Gordon"
 
"How are the splines on the cr

"How are the splines on the crankshaft and lower unit? Prop spins while in gear, right.
If water flows through the bottom tube and out the pisser there was no reason to pull powerhead, sorry if I lead you that way."
 
"yes prop spins while in gear

"yes prop spins while in gear and i pulled the power head to check the seal on the top of the copper water tube mate, was i right to do that ? but i still have no water through pee tube on tickover. a lot of water leaks though the muffs, would it improve if i drop the leg into a water but, could this improve flow through the pee tube.
regards Gordon"
 
"when we hooked a hose to the

"when we hooked a hose to the bottom of the tube and water came out the top pisser we then knew the seal on the top was good.

We now know it is in the lower end. The key way is in the impeller right, it likes to fall out if you don't know its there.

If that is fine, you are sure you got the water tube attached to the waterpump housing, yes.

Does tick over= idle speed, I'm running slow from last nights date with Lara, well she got me tippsee"
 
"the water tube is atached to

"the water tube is atached to the pump housing the keyway is in place (rotated by hand when impeller was fitted) and yes tickover = idle speed (sorry english term) and tell lara not to force all that beer upon you.
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"what was the part number on t

"what was the part number on the impeller you installed. It was a very tight fit right. Housing is not cracked, seal in housing still ok.

A merc blue band, light blue and dark blue with red lettering was made from 80 to 83.

Im gone for 2 days in 1hr, somebody else might have to help, you got me stumped"
 
part # of impeller 47-89983T w

part # of impeller 47-89983T was a tight fit had to rotate shaft to fit seams to fit snug. seal in housing is also a good tight fit it has got me stumped mate its a simple water system so why does it not work. thanks for all your advice mate i will keep you informed of the outcome.
Regards Gordon
 
"looks like the right part for

"looks like the right part for merc 50hp 4 cylinder, crosses over to sierra 18-3007 on this site under engine parts"
 
"Cheers buddy, can you tell me

"Cheers buddy, can you tell me, do i have to remove part number 31 to inspect the water jackets are clear?
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"right then. i have just taken

"right then. i have just taken the muffs off and submerged the leg in a barrel of water. just above idle speed i have a fast spurt of water from the pee tube, any thing faster and i have a fast flow. knock it back to idle and nothing, just above idle and a fast spurt of water. will this be ok to go ??"
 
"Gordon, still sounds like eit

"Gordon, still sounds like either a bit of a clog somewhere or even a hole in the watertube.

At very low speed (idle) the impeller uses simple displacement to force water up the tube to the powerhead. Any little leak along the way will let the water take the "easy way out".

At higher rpms it's centrifigal force that "shoves" the water up the tube. A minor leak would still leave enough pressure to actually feed the head and you would see "some" water coming out.

The flow should be relatively strong all the way through the power band kinda like when you turn on a garden hose. About half way open it's flowing good, simply the rate of flow will increase as you open the valve more - same with your outboard - you are looking for strong flow getting stronger - dribble is not what you want to see and indicates a blockage or leak.

From the diagram you posted above, if you remove number 8 (the waterjacket cover), you can see all the water channels and look for build-up, blockages etc...."
 
"graham, thanks for your reply

"graham, thanks for your reply buddy, i do appreciate your help mate.one more question though before i stwrt the major strip down. the part you indicated (with the spark plugs in) to get this part off i have to split the power head and lift out because it sits inside the lower cowling, am i right in what i say or is there an easier way to get this part off ??? thanks again.
p.s. what is the time difference between us . i am in the uk are you in north america ??
regards gordon"
 
"I'm Canadian Eh!

Just

"I'm Canadian Eh!

Just remove the plugs and as long as you can get a wrench or socket on the watercover bolts you can leave the head in place and attached to the exhaust housing - a universal on a socket may help.

These are only attached with about 10 ft pounds of torque and only really keep back the water circulating around the cylinder head itself (which is a part of the upper block). If I'm rememberin' correctly, those bolts are only about an inch long and will easily clear the lower cowl when fully undone...."
 
"Gordon, you said the impeller

"Gordon, you said the impeller was a tight fit on shaft, it has a key that locks it to the shaft. Please check to see the key is installed."
 
"Graham thanks again for the q

"Graham thanks again for the quick reply, i will remove the water cover next.

JB Thanks again mate and yes the key is located correctly. held it in place with grease.

Regards gordon"
 
"Right the weekend is comming

"Right the weekend is comming so its time to get to the bottom of my problem, so guys am i right in saying that if i remove part no 8 in the diagram above i will be able to check the water jacket for blockages also this part can be taken off in situ ?? the other question is when the bottom of the leg was off and i had a garden hose connected to the water tube ( held in place by my hand) water came out the pee tube but most of the water was comming down inside the leg onto my hand. is this right and is the the exhause route? cheers guys.
Regards Gordon."
 
"part 8 will come off, the low

"part 8 will come off, the lower sect of the engine cowl has a little wiggle room if you remove the 4 stailess steel bolts in back and the 2 on the front that support the upper cowl brackets.
I don't think you need to do this. I think the water tube is cracked or the top seal of the tube is bad.
I would hook a hose to the tube, make sure it fits the tube and doesn't leak, all the water should either go out the tell tale or run down the exhaust tube.
Pulling part #8 is easy and cheap, but there would have to be something large in there to cause this problem. Just my guess.
Did this engine have a chance to freeze before this problem happen? Was this engine overheated?"
 
"JB thanks for your fast reply

"JB thanks for your fast reply it is appreciated. the engine did get hot and graham advised me that the top seal on the water tube may have melted. so i lifted the powerhead out and checked, it was sound. as i say anything just above idle speed and water is good its just when you return to idle flow stops.
Regards Gordon"
 
"if the flow is good above idl

"if the flow is good above idle than the powerhead cant be blocked, my guess. Did you remove the thermostat cover yet to look around?"
 
"I give up. If you don't f

"I give up. If you don't find anything check the gaskets on the exhaust tranfer cover 28,29, and 30 on the top picture. If something is blown there water can bypass block and go right down exhaust. Might as well buy a complete gasket set."
 
Is it possable the houseing is

Is it possable the houseing is worn or impeller is not installed right and did he rotate motor clock wise will putting impeller in ?
 
"william, impeller is in right

"william, impeller is in right with the key and was a tight fit, the housing looks fine. i am going to launch her tomorrow because as i said fractionaly over idle and she spurts fine, so she is going in the water. if i have any problems she will be comming home and having a major strip down before the spring.
Regards gordon"
 
"right guys took her out today

"right guys took her out today on the solent, ran her almost full throttle for 2 hours she ran fine. when i came back to shore i noticed no water pee tube switched her off and loaded on the trailer. got home lowered her into a water but to flush her through and fast flow from pee tube again. its got me beat. why should it work fine for 2 hours then stop and then start again ???"
 
"Idle curiosity, what are your

"Idle curiosity, what are your idle rpms?Maybe they are a tad low and not pushing the water up the tell tale tube? My beautiful merc800, when its all in one piece, idles at 650rpms or there abouts and just about spits water.I'm not sure what your idle rpms should be."
 
"Noel thanks for your reply ma

"Noel thanks for your reply mate, not sure what the idle speed is fella, i have no rev counter. should i try and set the idle a bit faster then ??
regards gordon"
 
"If you have no rev counter,ta

"If you have no rev counter,tach to them on the other side of the puddle, if when you shift into forward and she doesn't try to hang herself, she's set about right.But if you advance her just enough to spit water you are sure the water is circulating.Might increase your fuel consumption a hair."
 
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