'75 50Hp Blockage in water chanels? Any Ideas?

[walkingfish]

Hi,<br />I have purchased as mentioned a 1975, 50Hp, 4 cylinder Merc, it needed some attention, but the price was right.<br /><br />Everything on this motor was corroded, i have had to use gas to free up the swivel tube, pull the starter apart and clean out all the rust and dust, it was siezed, and replace most of the wiring as it had rotted.<br /><br />I finally got he wee girl to start, and there is no water coming out of the tell-tale.<br /><br />I thought this would be an easy fix so i pulled the rubber tell tale hose, and sure enough it was full of crap, with that clean i tried again, still no joy.<br /><br />I pulled the leg off and inspected the pump and impellor, they are all good, so i hooked the hose up to the water inlet pipe and i got water out from the leg, i could also blow easily through this pipe.<br /><br />I then hooked the hose up to the tell-tale rubber hose in an attempt to "reverse flush" any crap that may be blocking the tell-tale, and whatever is blocking it didn't budge, its still blocked.<br /><br />Now i am thinking of removing the water jacket from the top of the cylinders to hopefuly clean out any blockage.<br /><br />Has any one got a better idea??<br /><br />Is there some chemical i can use to disolve the crap?<br /><br />If i pull the water jacket off, will i be able to unblock most of the channels? or will i need to strip it down further?<br /><br />Thanks Guys,<br /><br />Brad

 

[walkingfish]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

^^

 

[walkingfish]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

Well know i have a new problem.<br /><br />I have removed / snapped most of the rusty bolts from the water jacket, but the two bolts at the bottom are covered by the cowl, so i cannot get at them with sufficient force.<br /><br />Do i have to remove the powerhead to get at these, or is there a way to remove the cowling or drop it enough to get at them?<br /><br />Cheers,<br /><br />Brad

 

[phatmanmike]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

read some of my older posts from last month in mercury forums... i had same problem. i removed the cylinder covers and found GOBBS of sand and sea shells in there, blocking the water flow

 

[Chinewalker]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

In for a penny, in for a pound. Pull the powerhead and remove the bottom two bolts. Lots of propane heat and penetrating oil should help extricate the bolts. Go slowly and carefully when drilling out the other bolts, too...<br />- Scott

 

[Chris1956]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

W-Fish, You need to pull the powerhead. This will allow you to get the other bolts out, and flush out the cooling system portion of the block. Look closely at the bolts that hold on the cylinder head water jacket cover. The block was cast shcu that there was space behind the tapped portion of the cover bolts. I was able to drill through the existing holes and use through bolts with nuts to reattach the cover.

 

[walkingfish]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

Chris, Chine, amd Phatman,<br />Thanks for you replies, most helpful!<br /><br />I am going to go ahead with the removal of the powerhead, i have undone all of the bolts except the gearchange nut under the carbs.<br /><br />how heavy is the power head by itself, and how "stuck" to the lower unit is it likely to be?<br /><br />Will i need some kind of lifting device to attach to the flywheel to pick it up, or would a couple of strong mates and a few beers seperate it??<br /><br />Thanx,<br /><br />Brad

 

[walkingfish]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

^^

 

[erniex]

Re: '75 50Hp Blockage in water chanels? Any Ideas?

Just pulled the powerhead off my 73/850. I was working alone and had to use a come-along attached to a support to lift the P/H off. After removed and on the ground, it weighed about 100lbs - I'm guessing. I could pick it up and put on workbench. Would think a couple of guys could lift it off - just awkward to handle.<br /><br />Removed the water jacket and broke two bolts - drilled them out and Helicoiled them - worked great - just don't overdrill the holes into the block.<br /><br />Good luck!