Blown 150 VMax and new break in question..Rodbolt?

[Captron904]

Hello, Capt. Ron here from Florida.
I have a 2005 150 carb v max that has around 530 hours (charter boat).
I was running WOT last week in very cold conditions (for here) 25 deg air temp and 45 deg water temps, motor lost power and locked up after 5 minutes of running wot. Mechanic and I checked and looks like all cylinders ran dry of oil...white chalky plugs, and one really bad cylinder, # 5 i think..... my question is could air temps being so cold effect the viscosity of the oil being injected? Carbs look great and although mechanic replaced oil pump, it looked ok as well. Just bugs me what caused it.

I had a new power head installed, so need to break it in..any suggestions?
Thanks in advace guy's!

 

[rodbolt]

Re: Blown 150 VMax and new break in question..Rodbolt?

normally,oil failures tend to destroy the crankshaft and rods long before the pistons give up.
can you post some pics of the pistons? yamaha has some extensive video traing materiel on piston, and other part, failure analysis.
most techs have never seen them but they do exist.
if your using yamalube 2m it should work ok as long as the remote and engine oil tanks get the regular maint at the proper intravels.
sounds more like a fuel issue.
did the tech take a fuel sample and test it foe ethanol?
if not have it done or buy the 12 dollar tester and do it.
we find that the colder the weather the faster the watery E crap falls out of solution and the base stock of gasoline is now to low and starts detonating pistons.
if your alarm system is working you cant really run the system dry of oil without an alarm and RPM reduction.
at RPM reduction due to sw3 closing you still have enogh oil for about 20 min before its actually a dry run.
however you can ice up any moisture in the system,fuel or oil, and create a lean condition.
for breakin, either follow the owners manual or your technicians written instructions.
if you carefully follow the owners manual for breakin your covered,same with your technicians WRITTEN instructions.
verbal instructions tend to be a waste of breath.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Rodbolt,
thanks for the response, I'll get more detailed info and try to get some pics on the powerhead and post it. I didn't know about the ethonol tester, will look into that. We did drain the seperator and didnt see any visible water.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Could you give more info on the remote oil tanks? I have never had them serviced or even knew they needed to be.

also, before the motor let go, it was smoking pretty good a few day's prior when I was idling around, when I got home It appeared that the manual choke was pulled out maybe a 1/16th " I remember thinking that it seemed like that was not much movement to even effect the carbs, the next day all was normal so I assumed it was the choke pulled out slightly. My mechanic said he pulled the manual choke slightly, trying to see if the carbs moved and said it didnt see any change. He did replace the oil pump also

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Not sure if I was clear.....it was smoking just one time (event) then next day normal

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Where can I get the ethanol tester?

 

[rodbolt]

Re: Blown 150 VMax and new break in question..Rodbolt?

I got mine from a briggs and stratton dealer but several other companies make them. they run about 12 dollars or so.

 

[m21mca]

Re: Blown 150 VMax and new break in question..Rodbolt?

I have just had my powerhead (Vmax 175tlry) rebuilt due to a failure in #2 cylinder. The failure was at the crank and rod bearing, the rod cup was pitted, the crank was pitted at same area and there was cylinder head scarring due to the metal from the crank & rod connection. I had this cylinder bored .020 over and all parts replaced with exception of 5 rods and 5 pistons. THe question I have is why this would happen, the "bad metal" response I have heard does not seem feasible. Is there anything I should check prior to too much operation. The new rebuit is running fine with about 1.5 hours of double oiled break in operation per manual. Could this be an ethanol related problem? I am now running stabil. Any info is greatly appreciated.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Here is an update on my ongoing situation:
Got 18 hours on new powerhead (150hp Yamaha V Max Carb) but rpms at WOT still around 5000. Found the fuel hose kinked between the fuel tank and wall of boat yesterday. The fuel line was run from the tank and directed between a gap of a little more than 1/4 inch..... Ran a new fuel line and presto....5700 plus rpms easy.
The boat is a 2000 Key West Stealth, I am on my second motor and third powerhead because of this. I'm at a loss for word why someone at Key West Boats would run a fuel line down between the tank and boat wall like that????
So, The motor runs awesome, except at 5500 rms it will shudder and drop down to 5100 everytime. I've replaced the fuel pumps, rebuilt carbs, and replaced plugs, sounds electrical like plug wires...any ideas? also was smoking a few times while idling, but didnt notice the motor missing

 

[rodbolt]

Re: Blown 150 VMax and new break in question..Rodbolt?

what I cant bekive is your on your 3rd power head and no one has done a fuel system vacum test.
its simple and the tool is an essential tool automatically sent to all yamaha dealers whether they want it or not.
it consists of an electric pump,flow meter and vacum gauge.
simply attach it to the lower lift pump intake hose,route the discharge back into the tank,turn the pump on,turn the vacum gauge on, adjust the flow regulator for your engines reccomended flow rate and read the system vacum.
dont even have to start the engine.
simply doesnt get any easier.
ALL my powerhead jobs get tested and this machine works on ANY hull design and ANY gasoline engine with a fuel line.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Rodbolt,
The first motor (115 cab Yamaha), I had the powerhead replaced by mechanic A and that powerhead crapped out and mechanic B installed current motor (150 v max carb) in 2005 and also replaced recent blown head last month. I think my current mechanic ran the vacuum test when he installed the 150 v max back in 2005, but not sure.

Currently the motor runs good, but when I hit around 5000 plus rpms, it will surge up and down rpm wise, and run like its running out of gas, rpms fall below 4600 but will pick right back up when I throttle back down slightly. Also was doing the same right around 3200 almost everyime I came down off plane.....sporta skipping and surging, kinda like flipping a switch betwen 5000 and 4600 every second or so when it's having that issue.
We replaced both fuel pumps, adjusted carb floats, replaced plugs.
My gut seams to think it's electrical like plug wires or plug boots. Power picks right back up after it bogs down. Is ther a jet or something in the carb that would cause this at a higher rmp?
It's really got me baffled?

 

[99yam40]

Re: Blown 150 VMax and new break in question..Rodbolt?

If you want to make sure it is still not the fuel supply system test it your self.

http://forums.iboats.com/showthread.php?t=283363

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Great info on that link, thanks. I plan on doing the vacuum check this week.
I never thougt about an air leak in the fuel system, although I still suspect my problem is electrical somehow.

 

[rodbolt]

Re: Blown 150 VMax and new break in question..Rodbolt?

your describing a classic fuel problem not an electrical one.
that motor is pretty basic on electronics.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

I guess I will look at running off a remote gas tank to illiminate anything in the boat tank?
After we found the kinked gas line, we ran a new fuel line and motor still surged at higher rpms and wouldnt get over 5100 rpm. We replaced the spark plugs and ran again and rpms were all of the sudden way up, which is why I sorta thought something with the plug wires because thats was the last thing we messed with before it ran great.
Would air in the system cause it to surge and drop rpms?

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Does a 150 VMax carb have an oxygen sensor?

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Going to also replace plug wire boots tomorrow, I'll post up what we find.

 

[rodbolt]

Re: Blown 150 VMax and new break in question..Rodbolt?

V150 has no o2 sensor.
a VZ150 does.

 

[Captron904]

Re: Blown 150 VMax and new break in question..Rodbolt?

Update, found crispy stator, new one on order. Will install and run Friday.