Yamaha 20hp cooling problem

[luddovitch]

Now I've checked under the exhaust jacket and I thinked I found the problem.. The gasket material is not good enough. Look at this pics:


As you can see on this pic, alot of oil at the bottom of the gasket. This is the gasket located closest to the Engine. Also the most part of the gasket is wet.
13843526_10209939559151729_376243727_o.jpg
Also oil at the bottom of this:
13838335_10209939559191730_1265570492_o.jpg
Here is a pic of the cooling lines, pretty coroded:
13839753_10209939559031726_1115724218_o.jpg
Also a pic inside of the Engine, alot of oil everywhere, is this normal?
13633435_10209939558391710_904489313_o.jpg

[TownsendsFJR1300]

Yep, that gasket didn't hold...

And why can't you use the OEM gasket??

As for the oil, looks normal to me, its a two stroke. Pistons and rings don't look bad either from what's visable

That exhaust is what is blowing out into your cooling system... Besides the pisser pissing poorly, the exhaust pressure is working AGAINST the water pump. Again, there's much more exhaust PSI than WP pressure, especially at higher RPM's...

I don't know if Yamaha calls for sealer on that gasket BUT, Yamaha makes a great case (no gaskets) sealer that once set up, works extremely well... That with a new gasket and a super clean surface should solve your issues...

[luddovitch]

Yep, that gasket didn't hold...

And why can't you use the OEM gasket??

As for the oil, looks normal to me, its a two stroke. Pistons and rings don't look bad either from what's visable

That exhaust is what is blowing out into your cooling system... Besides the pisser pissing poorly, the exhaust pressure is working AGAINST the water pump. Again, there's much more exhaust PSI than WP pressure, especially at higher RPM's...

I don't know if Yamaha calls for sealer on that gasket BUT, Yamaha makes a great case (no gaskets) sealer that once set up, works extremely well... That with a new gasket and a super clean surface should solve your issues...

Do you mean the original gasket from yamaha? I think it's to expensive, that's why I wanted to try with this much cheaper material. The original is about 570 swedish krons, wich Is about 65 us dollar for one gasket. But I will probably have to buy the gaskets... But i'm glad that I probably found the issue with the engine.

Thanks again for all the help TownsendsFJR1300

[TownsendsFJR1300]

Your welcome..

Yep, Yamaha, or any marine part is generally not cheap, but, gasket wise, you can't beat an OEM gasket.

Figure you'll (hopefully) only be replacing it once, part of boating and certainly not worth damaging the engine for $65...Do it correct once and be done with it.

IMO, its not worth the headache / down time for a couple of $'s


BTW, With that side cover off, do you see any where at the bottom coolant chamber where water could be coming out by your engine mounts (first video I believe)? Maybe squirt some water in that lower water jacket and see if it trickles out the front of the engine..

[luddovitch]

Your welcome..

Yep, Yamaha, or any marine part is generally not cheap, but, gasket wise, you can't beat an OEM gasket.

Figure you'll (hopefully) only be replacing it once, part of boating and certainly not worth damaging the engine for $65...Do it correct once and be done with it.

IMO, its not worth the headache / down time for a couple of $'s


BTW, With that side cover off, do you see any where at the bottom coolant chamber where water could be coming out by your engine mounts (first video I believe)? Maybe squirt some water in that lower water jacket and see if it trickles out the front of the engine..

You mean the water coming from the lower front of the mid section? I will try that.

[TownsendsFJR1300]

You mean the water coming from the lower front of the mid section? I will try that.

Yep, I don't believe water should be coming from there..(I might be wrong)..

[pstephens46]

Yep, that gasket didn't hold...

And why can't you use the OEM gasket??

As for the oil, looks normal to me, its a two stroke. Pistons and rings don't look bad either from what's visable

That exhaust is what is blowing out into your cooling system... Besides the pisser pissing poorly, the exhaust pressure is working AGAINST the water pump. Again, there's much more exhaust PSI than WP pressure, especially at higher RPM's...

I don't know if Yamaha calls for sealer on that gasket BUT, Yamaha makes a great case (no gaskets) sealer that once set up, works extremely well... That with a new gasket and a super clean surface should solve your issues...

What sealant? 518?

[TownsendsFJR1300]

What sealant? 518?

Yamabond #4 is what I've been using..

This is from my F150 shop manual but I use it mostly on the bike and small engines:

[luddovitch]

Just got the new gaskets home, they almost feel like some kind of hard rubber so im not sure if its gonna be necessary with sealant. But I guess it wont hurt neiter to use it..

[TownsendsFJR1300]

If you have definite pitting, uneven surfaces, I'd most likely use it.

I don't know if its called for in the shop manual. If not and the surfaces are good and clean/no pitting your likely ok without it.

A straight edge to the block surface to see how flat it is wouldn't hurt..

I know it takes a little while to set up. If using the yamaha stuff, I'd let it set overnight for a super tight seal..

Please post back your results!! And good luck

[luddovitch]

New gaskets installed. I didn't use any sealer, the surface looks good and straight. The water from the pee hole has imrpoved a little bit at idle, but it hard to se if it is any better att higher rpm, but it is still more like a spray than a steady stream. But with the termostat cap off I cant see any exhaust anymore so thats an improvement. Here is a video:
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[TownsendsFJR1300]

Well, I know you inspected the water pump but, I think I would replace the impeller (use the entire kit) and probably the housing itself, just to rule out the pump. It doesn't take much to loose pressure/volume.

I don't like throwing parts at it but the pump should be replaced occasionally in any case. You didn't mention how old it is but its cheap enough.

[luddovitch]

Yes, you are right about that. The impeller was changed just before I bought the engine, last autumn.

I took the impeller housing apart again, and im not sure if I mention this before but it is some grease or oil around the outside of impeller housing and inside of the rig. Look at the pics:

13646926_10209981313955573_1007635150_o.jpg

13840455_10209981313435560_1257634070_o.jpg


Here a pic of one gasket that is a little bit damaged:
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[cpostis]

Yes, I tried it without the termostat before and could feel air pressure when I held my hand over it, i'm gonna try that again though just to be sure. I Think it's exhaust gasses, it has the same color as the exhaust gasses.

Hm, okay I will run it with more water in the barrel, thanks for the tip. I've checked the impeller yesterday and the impeller itself looked fine to me, but im not sure what to look for on the other parts in the pump assembly.

Luddovitch,
In viewing your latest video, I'm not sure you are filling the water barrel enough. Look at the pic. I believe this is like your lower unit? The red outlined areas are the water intake and water pump. When running in a tank, you must not only ensure water level is above the intake, you must also ensure the water level is above the water pump (at or above the green line).

Others, please confirm this. I don't see anything that tells me these water pumps are "self priming", if when started in a tank (or even in the water) without the pump housing being below water level and not flooded?

[pstephens46]

Mine will suck water without water pump housing below waterline. Not good though as it would seem the impeller would spin dry for a few secs prior to priming. F150 btw