MJ's Blown Piston - Page 2

Skools Out · #1 06-02-2006, 11:21 AM

MJ's getting a LIKE NEW Yamaha 150 from BR

bigshrimpin · #2 06-02-2006, 01:32 PM

MJ - Stick to your plan . . . . Tear it down, part it out, and sell everything. Buy BR's and don't reuse your carbs unless you rebuild them first. Leave the oil injection off too. You'll have some fluke/bass money after a few trips to buy another parts motor.

Your more than capable of rebuilding that motor, but the smartest/quickest path to the water is BR's Yammie!!

macojoe · #3 06-02-2006, 05:07 PM

Ok I want to thank all for your help!!

1. I do ot think it was a oil issue cause I was using oil, the level was lower then when I started.

Yamaha does ot mix oil with gas it is a derict oil injection.

2. Carbs?? If the middle carb runs the middle cylinders then why is one at 0 and one 120 ??

3 *yes it over heated big time!! *But why?? *Water was pissing, and the thermostas check out ok in a pot of water boiling at 180*

So if not oil, carb, or water then what?? *I still think there was a internal break down of some kind??

So I agree, that it was the ring!!

I also think that fixing 1 of 6 cyl will be nothing more then problems with the remaing 6, on a 18 year old motor.
I would only fix if I was going to sell it!

If I had got the parts motor I might have tryed over the winter to build it and then sell in the spring??

But since it that did ot work out I will sell the parts and go with BR motor!

Geekie1 · #4 06-03-2006, 05:55 PM

MJ, I was expecting a hole in the piston!! Could be a broken ring, however, I think that the most likely problem is a bad reed. Running lean can cause a reed to burn up which would also give you zero compression on that cylinder. You can check the reeds by pulling the center carb and look down the manifold barrels to check the reeds on the bad cylinder and comparing them to the good cylinder next to it. To get a better view and a little more work, you can instead pull the intake manifold with the three carbs still bolted to it. You will need to disconnect the fuel lines to the carbs, oil lines to the manifold, disconnect the carb linkages, not a difficult job. If the reeds are damaged, you will definitely see it when you pull the manifold, carbs, reed as a unit!! Reeds perform a similar function as valves on a 4-stroke. To repair the reeds is a job in the lower hundreds of $. The cylinder wall does look a little screwed up though so some work on that cylinder will probably be necessary. If the reeds look good, you most probably do have a broken ring. Yamaha oil fuel/oil is not mixed in the carb but in the intake manifold. I think the oil system on the Yammie is pretty simple and bullet-proof. If the oil level sensor lights on the helm instruments is working (self test when starting) and if you get low in the main tank or the small tank on the engine, you should get a yellow or red light and the rpm's of the engine will drop to 2000rpm. There is an article in Bass and Walleye magazine that explains the whole thing. Monday I will post the URL that has the article. Although an oil pump could fail, I have never heard of one failing on a Yamaha. But I guess I haven't heard of alot of things.

macojoe · #5 06-03-2006, 06:11 PM

Thanks Geek,

But all oil systems were go!! oil level was down in the tank at end of day.

as stated above, this is a dead thread as I am not going to be fixing the motor at all.

I will ck the reeds as I plan on keeping the carbs for spares on BR's motor, they have the same numbers.