[brightside]

However, when scheduling the time to meet with the mobile mechanic we talked a bit - he knew we were doing a sea trial today. The one thing he said I should be sure of is that the engine topped out over 5000 RPM. more

[marcelus23]

We did the sea trial with 3 adults, 2 small children and a quarter tank of fuel. We had decent winds and a 1-foot chop in the bay (Sarasota). here

[humble]

Hello all - first post here! I am purchasing a 2000 Grady White 208 Adventure with a Yamaha ox66 150 engine that has approximately 400 hours on it. The boat and engine seems great. Tomorrow, I am meeting the mobile mechanic who will do the compression check on the engine then she is ours. more

[markhudsn36]

BOTTOM LINE - We rode WOT for about 40 seconds and the engine never got over 4700 RPM.

[mrb]

I'm trying to get an understand at what point the RPM limiter would engage on this engine. It runs great up to 5600 RPM at 3/4 throttle making around 38 MPH GPS but anything above that it dies off to around 5000 RPM. more

[Vinnie]

Is it the rpm limiter engaging at 5600 RPM? Some have suggested the RPM limited engages at here

[donaldmoreg]

I'm aware that I'm probably under-propped because I'm using the prop from the 200 I had on the boat which was replaced by this current engine. It would turn 5000 RPM - maby 5100 RPM. more

[m86]

[gusti]

hi this is my first post but i will say that i have done research and used the search fuction. my motor is an 01 0x66 225. it has 3 new oem lp pumps, the injectors were just cleaned ultrasonically. has a new tp sensor installed. no water in fuel. the high pressure pump did seize up but i was able to free it up soaking it in fuel injector cleaner. more

[meldavies88]

the boat will start and idle perfect all day. when it gets on plane around 3.5k to 4k rpm it will cruise there for a minute or two then just shut off like the lanyard was pulled. it will not build fuel pressure again unless you cycle the key off and back on. the mechanic and i water tested the boat with a fuel pressure gauge and test light. the fuel pressure is at 0 when the motor shuts off and he says ground is lost after the pressure falls. he says hes never seen this before. he determined high pressure pump based on the way it just looses pressure and given that it had seized before. i put a new oem yamaha pump and new vst screen in and water test the boat today. same exact thing happening. plane out to 4k and after 2 minutes shut off again. i have the factory manual and tested the inline high pressure pump resistor which is in line with the blue (negative) pump wire. spec is .53 to .57 ohm. it varies on my dvom from .5 up to .7 ohms. i was not able to check the resistance while the boat was running. i need this boat fixed asap, fishing tournament coming up and paid entry fee already. please help!! here

[KInkade341]

more

[judy10perez]

[kat]

So I went and talked with my local Yamaha dealer today. the sugguested that I fill the oil reservior on the aux tank and use the grey primer switch to fill the engine reservior. also change my fuel water seperator again. it could be plugged with crap. Will see if it works it would be nice if it was a simple fix like that. if not I was told to bring it into the shop the mechanic thought the vst was prob gummed up. If it was the low pressure fuel pumps the engine wouldnt even idle right. He didnt have much to say about the 02 sensor when I suggest that. here

[Jevens55]

I think I put a post on here about it a while back, I had a long post about it on THT, (Im in Bahrain right now, so some sites are working, some not so i cant get access to THT to post the link) Do a search on THT for authors "walden75" thats me, you'll see my long read and pics etc on it from the May/June time frame this year. [links]

[v-tim]

Hey guys I have been dealing with power issues on my 2000 Yamaha ox66 250. The last few trips out I have been cruising along around 36k rpm when all of the sudden the motor bogs down like it’s going to stall. As soon as I backed down the throttle 15k or to neutral the motor ran fine, power up again and it would be fine. At first I thought it was sucking air into the fuel lines starving it of gas, so the next time it did it I had my friend drive and I felt the primer bulb which was still rock hard. This weekend I had a complete power loss and was unable to recover. I limped back into the dock, it ran somewhat fine at lower power just above idle, add a little power and it would cycle between running and bogging down almost rhythmically. The primer bulb was still rock hard. When in neutral I can reve it up and it cycle’s fine, reverse doesn’t seem to have the symptoms either.

[nicoleblair112]

And yes I always use RingFree, and use ethanol Stabil in the gas. here

[aurelian]

I hope that gets it for you, if not I would certianly check LP pumps, they are an easy test, a 10mm wrench to losen 2 bolts each, prime bulb, see if fuel leaks out, if so, its bad.