Yamaha Outboard Repair

cianoc07

Hi, I have a Yamaha 75hp engine on my lencraft. The engine is over heating as it is not being cooled correctly due to a build up of salt. The impellor has ben changed and the engine was flushed out in an attempt to clear the blockage. It was brought into a local dealer who flushed it out even using vinergar but was unsuccessful.

is there any thing else to try to free the blockage. Take into account this is an old enough engine probably manufactured around the 80's so taking the head apart would lead to bolts shearing etc.

Thanks

fergal.b

I have used the inner steel cable from the brake cable on a pushbike by feeding it up through the pee hole twisting it as you go and taking it out and give it a clean as you go, when your done use a 10mm syringe filled with water and push it in the pee hole, use it like a plunger to force water up and down a few times then suck it back out with any bits of dirt, do this a few times and see if it helps if that doesn't work you might have to take off the water jacket very carefully as these bolts snap :eek:
Was it like this before you got the impeller done, could it be that the impeller is slipping on the shaft "key left out" or that the tubes aren't lined up right.




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cianoc07

No that has been checked its not that! impeller was changed aswel...just wondering is there much work taking the head apart to expose the cooling channels

fergal.b

If you are having the problem as soon as you start the engine the thermostat will not have opened yet to let water into the power head so the problem will be between the water pickup,water pump,,exhaust cover and the pee hole with some of it going out through the propeller or exhaust port. By the way have you plenty of water coming out of the prop or exhaust port and it's just the pee hole thats blocked ? I would also check the thermostat is working before having a go at the head.





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breghall

I'm betting on a blocked up thermostat , and its housing.....all caked in a salty residue....

cianoc07

Right so lads..just put a new battery in but still no power what so ever! not even a turn over or tilt the engine...any ideas?

breghall

checked the fuses?? should be inside on the wiring harness on the engine.

fergal.b

Also make sure it's in neutral, the battery is charged, all connections are good and the kill cord is in place.





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cianoc07

Started first go after 2 years! it was the fuse!! thanks lads! so i was at the boat all day. Steering is seized, Thermostat is gone and no tilt or trim.

1) The steering is single cable...moves at engine when bar is disconnect..but doesnt move when turning sterring wheel..i think the cable is seized somewhere inside the pipe??

2) Took off the thermostat plenty of water being pumped up (Thank god) put thermostat in boiling water no budge!!! Where will i get a new one for Yamaha 75hp 75AETL???

3) No tilt or trim.... relay and motor working away but no movement.. I can raise engine manually by lifting it...Could this be due to lack of or no Hydraulic oil??

fergal.b

The steering cables are prone to lock up where the stainless steel end goes into the aluminium tube on the engine the two metals don't like each other and often cause a galvanic reaction, you could try disconnecting it from the engine and prop it up straight and spray it with WD40 so it runs down into the tube a bit of heat on the tube might also help.

Any of the marine shops should be able to order a thermostat for you.

I'd say it's lack of oil or air in the oil alright.




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cianoc07

Crap im after disconnecting by the steering wheel...pain getting it back on! Il do that so and tap with a wooden mallet!

Thanks for the info lads! very helpful!!!

breghall

as fergal siad , i'd diagnose the steering problem where the tube is inserted at the engine..

with regards to the tilt and trim, you should n't be able to lift it manually, so i reckon you're low on oil, find the filler screw , top off the oil , circulate the engine up and down a few times and redo until oil not air starts to come out from the screw..

personally when i look for a part i usually ebay it..... may take a week or more longer to get to me but it can be half the price if not more .... i'd try here first for the thermostat if you're not in a hurry ....( Sorry irish marine part suppliers but some of you are absolutely ridiculous in cost)

cianoc07

Can i use power steering fluid for the fluid in the tilt and trim??

fergal.b

You should be ok OMC use the same oil for steering and tilt trim, you can also use 10W-30 or 10W-40.

cianoc07

Would this be the correct thermostat for my outboard. its a yamaha 2 stroke 75hp engine code 75AET

http://www.ebay.com/itm/380530557960?item=380530557960&viewitem=&sspagename=ADME:L:OC:IE:3160&vxp=mtr

Also filled the tilt and trim with oil...attempted to move engine up and down but no success...no leaks to be seen and hydaulic pump/motor can be heard. Rams moving freely so not seized. when i took off the cap at one stage there was a build up of pressure the nut flew off. is it just a case of keep adding oil and attempting to move up and down?

fergal.b

That looks like the right one alright.

You might have to bleed it by turning the relief screw and lifting the engine up and down by hand to make sure there is no air trapped keep topping it up as you go.

cianoc07

I turned the release screw alright to raise it up and then locked it again. so i should release it a few times and raise it up and down.

fergal.b

Yea it might take a few goes to work the air around.

cianoc07 wrote: »

I turned the release screw alright to raise it up and then locked it again. so i should release it a few times and raise it up and down.

cianoc07

Cool i will give it a go see if it solves the problem!! Thanks

Glenalla

cianoc07 wrote: »

Hi, I have a Yamaha 75hp engine on my lencraft. The engine is over heating as it is not being cooled correctly due to a build up of salt. The impellor has ben changed and the engine was flushed out in an attempt to clear the blockage. It was brought into a local dealer who flushed it out even using vinergar but was unsuccessful.

is there any thing else to try to free the blockage. Take into account this is an old enough engine probably manufactured around the 80's so taking the head apart would lead to bolts shearing etc.

Thanks

http://www.saltawayproducts.com/

cianoc07

Hi lads,

great news the engine lives again after some work! I now have one last problem. The controls is a Yamaha 703 unit. The tilt and trim works but i think the spring is gone in it, as it tends to stay down or up. now im afraid that as the engine is running it will start to tilt up by itself.

Is this a case of a refurb or buying a total new swithc?!

fergal.b

cianoc07 wrote: »

Hi lads,

great news the engine lives again after some work! I now have one last problem. The controls is a Yamaha 703 unit. The tilt and trim works but i think the spring is gone in it, as it tends to stay down or up. now im afraid that as the engine is running it will start to tilt up by itself.

Is this a case of a refurb or buying a total new swithc?!

I would think it's a new switch as they are a sealed unit, the part number is 703-82563-02-00 and they are not that cheep have a look on ebay.




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deeperblue11

anyone know of a good mechanic in mullingar?? 8hp yamaha needs attention?????????????

fergal.b

deeperblue11 wrote: »

anyone know of a good mechanic in mullingar?? 8hp yamaha needs attention?????????????

I'm not sure about mullingar but Mick clinton not too far to drive http://www.clintonmarine.ie/




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cianoc07

Hi lads,


Recently bought genuine Mercruiser flushing muffs for the engine.
We usually run the engine in a large barrel of water. I just thought maybe that this would be a quicker method as apposed filling the large barrel each time. So i just ran the engine there with the muff's. They were correctly fitted and a good pressure of water to them.
Anyway as the engine was running i had my hand just on top of where the Thermostat is located. ie above the cylinders.
I noticed that it got hot quite quick in that area. Now in the barrel ive never noticed it get that hot.
There was a good flow from the tell tale. The engine was running superb all the days it was out and was flushed after each use

What are your opinions on these muff's? Do you use them? or do you stick with the barrel?

fergal.b

Are you running a mercruiser with an outdrive or is an outboard, as long as you keep the rev's down you should have no problem running on muff's I do it all the time. It could be getting hot there because the thermostat hasn't opened yet to let the cold water through the engine, the pee hole has it's own route that doesn't go through the thermostat.




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breghall

i'm not a big fan of muffs, always cause my engine to run hotter than if in a barrel. I use them to flush salt away for a few mins but if I was ever running for a long period I'd always use a barrel. Just don't like them at all...maybe i've bad water pressure or something but I always run hot and my Johnson tell tale only runs after thermo opens.

cianoc07

But if the head is hot, wouldnt the thermostat already open with the heat??

fergal.b

Depending on the engine they open at around 180 degrees so it's quite hot, what's your gauge reading.




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