Problems with VMax

[Cajun Skeeter]

My 2000 225 VMax has recently developed 1 or 2 issues (maybe related, maybe not).

I fished a tourney today and my boat started having major problems getting on plane. It just seemed to bog down and seemed to not have much power. The funny thing is that a friend of mine just bought a 2001 Champ with the same outboard (very low hours) and he is having the same problem. We both went to Toledo Bend last week and I'm thinking that maybe we got into some bad gas or something. Neither of us has an in-line filter, only the one inside the cowling. Any thoughts if bad gas would make sense? What should I do?


Second problem, I just noticed recently that my motor seems to be smoking like crazy and seems to be going through oil a lot faster. I think that this started before the Toledo Bend trip but I wouldn't swear to it. I need to do some more checking on my usage rate to be sure. Is 50 to 1 the target?

[21XDC]

Check the oil pump link adj... Replace the plugs with br8hs10's. Do a search on yamaha oil pump.

[EL Skeeter]

As Mike recommended BR8 HS 10's are one level hotter than what the book calls for.
Thus burn fuel better.

[Cajun Skeeter]

I've ran this boat for 3 years without this problem. Do you guys think that either "bad gas" or something related to too much oil just started causing the boat to bog down and loose power?

[Rich Z]

I would like to know in more detail what the symptoms are on you motor.
I’m having some issues also on my 02 ox66. Mine will idle fine until its warm and when I squeeze the throttle it boggs down until about 1500 rpm, and then it clears up and takes off. Runs fine at wot. So far I cleaned and checked vst including 10mic filter and high pressure pump, tested TPS, checked with different ecu, cleaned the o2 sensor, replaced 3 low pressure fuel pumps, flow tested injectors, checked compression, checked all wirers and connections and still same problem. Today I’ve found a faulty thermo switch witch tells the ecu to choke the motor thinking its cold after a warm up. New switch is on a way so I will update in couple of days. There are two of these switches located right on the thermostat housings. Put the switch in hot water then test with ohm meter. While testing with ohm meter, I had intermitted reading and some off the wall numbers comparing to the good switch. As far as smoke on these motors, well, I haven’t seen one that doesn’t smoke. Mine burns right at 40:1.

[Cajun Skeeter]

Rich,

I've just started having this problem so it's hard to go into much detail. It bogged down once last week when I was at Toledo Bend. I fished the next day and once since then with no problems at all. Sunday, I was fishing a tourney and the boat took off fine the first 2 or 3 times during the day. Around mid-morning, the boat started to have terrible power during takeoff...just kind of bogged down, low power and just slowly eases up onto plane. That happened the rest of the day everytime that I took off. The boat also feels a little weak at high speed although I didn't GPS it. I'll post more after I fish this Friday. The only think that I've done since Sunday was dump some water removal stuff into the gas tank to see if that helps any.

[Rich Z]

Hope you used sea foam and not some alcohol or ethanol base product that will most likely do more harm then good. I will test run my motor tomorrow. I’m confident that the thermo switch was the problem.
BTW I disagree with using a hotter plug then recommended. There is a high risk of detonation that can melt your pistons.

[disturbingiraq]

hey guys im having a similar problem just on a more grand scale. it all started the way yall are talking. just now mine wont even idle by itself and it seems like the engine is starving for fuel. is there a way to check the fuel pumps to see if they are working. mine is a 99 225

[Rich Z]

Installed new thermo switch, tested on the lake and still same problem. I know for a fact this switch was bad. Got to look elsewhere and am running out of options.

Mike,
Maybe you just need to turn up the idle adjustment screw located on starboard side about half way up on the throttle body linkage. Other option is to clean VST and filter on high pressure pump.

[disturbingiraq]

the idle is set havent moved it. i think mine is a problem with fuel pumps because everything else checks out fine.

[CCC050607]

I dont think its a gas problem. If it was, my guess is it would be missing more then anything else...Not bogging down.

[Cajun Skeeter]

Ran the boat again last night. Still having the same problem. The boat takes off very slowly and is very weak. It finally gets a little more power as the RPM's come up and then it gets up on plane. Runs sort of Ok but you can feel it kind of missing or something as the power comes and go's. I pumped out the rest of the gas today and will re-fill with new fuel for nest week.

My buddy was having a similar problem and is now running Ok. He got rid of his fuel and also said that he found a small leak in his fuel line.

[Cajun Skeeter]

It was "bad gas", whatever that means.

My buddy and I both got rid of the old fuel and put in new fuel. Problem solved!

Bad gas came from the Toledo Tackle store at Toledo Bend.

[Rich Z]

I got mine worked out also. My shift linkage was out of whack after changing LU and adjusting shift linkage because of clicking in a prop. Shift interrupt switch was engaging causing two cylinders to go out intermediately.