2003 Yamaha 115 four stroke

[03yamaha115]

Hi new to the forum but i just recived my grandfathers boat a 2003 blue wave with a 115HP Yahama 4 Stroke. The boat has not been in the water for 2 years. I have started the boat several times since my grandfather passed away about twice a year. The oil light has flashed since the first time i cranked it but no alarm sounded. checked the oil level was fine and it seemed fine like it was changed shortly before my grandpa got sick. I have taken the boat out 3 times, twice with no problems. The last time i had it out everything was going good went to a couple of spots and fished I went to go to another spot and the boat wouldnt plane off it bogged down only turning 2500 rpms. stopped the motor and cheked the oil level was fine and still looked ok. No water in the fuel filter. Started back up still wouldnt plane off rode back to the ramp at 1100 rpms about 20-30 mins at that speed got back to the house and the oil was a milky gray color. went and got a new oil filter and oil. changed the oil and put back in the water seemed like it acted a little better but still struggled to plane off and would only turn 4200 came back to the house and the oil is still milky. the temp light never came on and a steady stream from the pee hole. the alarm works it beeped for a second when i started it after i changed the oil. the oil smelled like gas. wasnt like water in oil like a car motor not brown more gray color. im an auto mechanic kinda new to boat motors wondering if any one has had a similar problem had a full tank of gas in it stilled smelled like gas put some B12 chemtool and ran it till i could put 6 gallons of fresh supreme in it the first time i took it out.

[boats.net]

Might check to see if tach is set for four stroke engine
Tach Settings.JPG
Sounds like you have a fuel problem, check fuel pump for bad diaphram, probably need to clean VST and injectors as well.

[03yamaha115]

blown head gasket

Well turns out i have a blown head gasket around number one.#1 75lbs,#2 150lbs #3 145lbs #4 150lbs. I am now looking for a factory assembly manual for my motor not one of those little Bullsh** books i am gonna get the parts and fix it my self. wHERE DO I GET ONE OF THESE BOOKS.

[99yam40]

YAMAHA MANUAL STORE


How did you find it was a blown head gasket?
Did you pull the head and actually see it was blow or did you just do a compression test?

A leak down test is a better test for cylinder sealing problems

[03yamaha115]

Compression test and there is moisture on the plug.

[99yam40]

I would do a leak down test before tearing it down just for the heck of it to make sure.
Hopefully you are correct and it will be a simple fix.
There are multiple things that can cause low compression readings like not opening the butterflies while spinning over and water on a plug could be a corrosion hole

[Sparkieboat]

you also should figure out why the head gasket is blown if it is. test your over heat alarm?

[03yamaha115]

The over heat alarm never went off was fishing and went to take off to another spot and it wouldnt turn over 2500 rpms idled back in checked the oil and it was milky. Im an auto mechanic so i know i have a problem with number 1 cylinder 75lbs compression and moisture on the plug the rest are 150 lbs and dry plugs. i hope its a head gasket and not a cracked or corroded head. my buddie runs a machine shop so he is gonna check out the head when i get it off. I also changed the oil and went back out ran a little better but oil was still milky. This boat has been sitting for 2 years since my grandfather passed away ive only put it in the water 3 times. Deffently gonna chek the sensor and replace the waterpump and thermostat and timing belt why im there. always had a good stream comming out the pisser.

[Sparkieboat]

these motors will get water in oil if they run too cool, as a result of an stuck open t-stat...do a leak down test before you pull the head. check your t-stat..it is p[probably stuck open.

[99yam40]

Sparkie,
I have heard of them making oil because of cold motor ,but not getting water in oil. Are you sure about that?

[Sparkieboat]

I think so..it happened to mine, I had some water in my oil. then found my t-stat was stuck open..replaced it, changed my oil and whala no more water in my oil. it is worth a check anyway. before he goes tearing down his motor.

[03yamaha115]

I'm gonna order a assembly manual this week I plan on checking the thermostat but why else should I have a week cylinder I ran the compression test 3 times and got the same results

[99yam40]

You never said how you were testing the compression
open the throttle some to make sure you are getting all the air needed

[03yamaha115]

More than just a head gasket

Well bad news turns to worse its a little more than a head gasket got everything torn apart and found that part of the cylinder wall is ate out and probably cant be fixed.

[99yam40]

Sorry to hear that.
from all the rust and corrosion it Looks like it was run in salt water and not flushed maybe