1999 Yami 200hp saltwater series 2 problems

[scottse55]

Hey guys I'm new to the forum but have a feeling im going to be speanding a lot more time on here we just bought a 99 Century 2600 with twin QX66 Yami 200's on it, the problem we are having is that after about a minute of running the motors past 3500 rpm the alarm sound and we get a loss of power which i think is going into limp mode so we shut the motors down for about a minute and start them back up just fine, it will keep doing this if we take it over 3500 rpm but if we keep it under 3000 rpm its fine all day, but bloody boring and take ages to get anywhere

The thing I don't get is that even thought we get an alarm nothing shows up on the gauge,


and one trim sensor is showing the motor is all the way up, could this have anything to do with whats going on ??

the fuel is pretty old as well,

Thanks in advance for any help you blokes may be able to give me.

Scott

[robert graham]

How long since water pump impellers, thermostats and pressure control valves have been inspected or replaced?....could be an overheating issue.

[99yam40]

Hey guys I'm new to the forum but have a feeling im going to be speanding a lot more time on here we just bought a 99 Century 2600 with twin QX66 Yami 200's on it, the problem we are having is that after about a minute of running the motors past 3500 rpm the alarm sound and we get a loss of power which i think is going into limp mode so we shut the motors down for about a minute and start them back up just fine, it will keep doing this if we take it over 3500 rpm but if we keep it under 3000 rpm its fine all day, but bloody boring and take ages to get anywhere

The thing I don't get is that even thought we get an alarm nothing shows up on the gauge,


and one trim sensor is showing the motor is all the way up, could this have anything to do with whats going on ??

the fuel is pretty old as well,

Thanks in advance for any help you blokes may be able to give me.

Scott

I would not be running old fuel to start out with, motors are too expensive.

Test your alarm systems to see what works and what does not to start out with.
Both oil level and over temp.

Then you can start troubleshooting what is happening above 3000

[scottse55]

The old owner said that they changed out the lowers two years ago but he doesn't really remember doing much to the motors at all besides that, the fuel tank is close to empty, so it will get a nice fresh dose of fuel tomorrow

wouldn't i get a temp warning on the Gauges if it was a cooling problem, or am i assuming too much.

Thanks for the suggestions I'll take a look again tomorrow at the motors and try some of the things you guys suggested

[99yam40]

Adding fresh fuel to old bad fuel will give you a bunch of bad fuel

If you do not know if the different alarms work, how can you expect it to warn you is there is a problem? Test to make sure.

Some motors have a low voltage alarm, might check voltage ECU is seeing when it happens

[rodbolt17]

pictures of your guage package would help.
could be the wrong guages,non yamaha guages.
could be the trim/oil harness is not attached correctly.
sounds kinda like an oil alarm due to a restricted remote tank filter.

[scottse55]

Ok so we are really having problems getting this fixed, so far we've checked the following

oil tank for correct fill time all seem good in fact while running flat out the tanks are at the perfect level,

Replaced both thermstats,

Replaced the, water pump impeller in the motor the we think is causing the alarm,

Replaced the trim sensor tab thingy on both motors,

Swaped both the temp switches and sensors over the other motor to see if it was a bad sensor but he alarm stayed with the bad motor,

Replaced the poppet valves in both motors,

New spark plugs,

Found the wire on one of the temp switches to be broken and repaired, the wire could have short out on the motor but we aren't sure,

New fuel filters,

All this and the alarm keeps coming back, this weekend we are going to replace the complete water pumps in both motors. Change out all the temp sensors and switches an just test as much as we can, we might even take off one of the heads to see what they look like,

Can anyone give us something else we are missing, remember we just get a alarm and the motor goes into safe mode, nothing shows up on the Yamaha gauges !! it's driving us crazy, I'm a little embarrassed to say im stuck,

[99yam40]

pictures of your guage package would help.
could be the wrong guages,non yamaha guages.
could be the trim/oil harness is not attached correctly.
sounds kinda like an oil alarm due to a restricted remote tank filter.

This is from a Yamaha master tech
if you do not respond to it there is not much anyone can help with

[scottse55]

I'll take some pics today, but they are Yamaha gauges,

[scottse55]

Ok so today we replaced both water pumps in both motors, complete kit not just the impeller, no change on the alarm but it's something we wanted to do anyway and we new it wasn't going to fix the problem, only took us an hour and a half so not a big deal,

Checked the oil system and everything reads fine per the shop manual,

While the engine was alarming we disconnected ond of the temp switches and the alarm went off, we also bypassed one of the temp switches and joined the wires together the alarm sounded but there was no visual overheat warning on the tacho,

The only thing I didn't do was take pics of he damn tacho for rod bolt

I'm not sure what else to do besides pull the heads or start looking into the ecu, as I checked out the temp swtiches and all four switches from both motors close at the same time,

Rodbolt you out there mate ??

[rodbolt17]

typically the overheat icon is in the speedo not the tach.
low voltage,low engine oil tank level and overheat can trigger the audible and RPM reduction.

[vanderwel]

Mate, sound like you have same problem as me. im picking one of my carbs is blocked. ive booked the boat into a workshop in 2 days time so i shoud know more then. keep me posted if you find anything. ive done a compression check and its all good.

[LarryPitt]

If your temperature alarm is going off and the engine does not seem to be overheating it may be the passage way under the water cover has become blocked. This happened to my 1989 225 Excel about 4 years ago and the local very experienced Yamaha mechanic speculated this could be the issue and he was correct. The passage around the temp sensor is very narrow on one side and mine was blocked off preventing water from flowing around the sensor well. I have not had any more issues with this since then.