I am having a devil of a time diagnosing an overheat on my 2004 Yamaha VMAX 150 (model number V150TLRC ). Initially, I had two problems – poor carb adjustment and an engine alarm (either overheat or oil alarm).
During my troubleshooting, I cleaned and adjusted the three carbs. That problem is solved. And engine runs a lot better now!
Still have the engine alarm to deal with. My gauges don’t tell me if it’s oil or heat causing the alarm, so I replaced the oil pump as it was old. Problem was still there. I used an IR heat gun on the heads during the next alarm, and the temp was in the high 160 range if I recall correctly. So – overheat. This is a 2004 and I run her in salt water on the Texas Gulf Coast, so I decided to replace a lot of the parts as they are over 10 years old.
I thought I might have a lean mixture problem, so I ran the boat this weekend and adjusted the fuel screws to a very rich mixture (4 turns out from closed). Still had an overheat.
Last night I removed the head covers and heads and inspected cooling passages. Everything looked pretty good for a 14 year old motor. No significant blockages.
The impeller has less than 8 hours on it, and the tell-tale is streaming water at full strength. Everything seems to be just as it should be, but I am consistently getting the overheat and limp mode after 5 minutes of operation at 4000 rpm. Allowing the engine to idle for 10 to 20 seconds will cool the engine enough for the alarm to turn off.
Anyone have any ideas of what the problem might be? I am totally stumped.
Rob
During my troubleshooting, I cleaned and adjusted the three carbs. That problem is solved. And engine runs a lot better now!
Still have the engine alarm to deal with. My gauges don’t tell me if it’s oil or heat causing the alarm, so I replaced the oil pump as it was old. Problem was still there. I used an IR heat gun on the heads during the next alarm, and the temp was in the high 160 range if I recall correctly. So – overheat. This is a 2004 and I run her in salt water on the Texas Gulf Coast, so I decided to replace a lot of the parts as they are over 10 years old.
- Replaced Water Separating Fuel Filter
- Checked Fuel Ball – all okay
- Checked fuel flow to carbs (using Fuel Ball) – all good
- Replaced Oil Pump (remote tank)
- Replaced Spark Plugs
- Replaced fuel pumps
- Replaced Thermostats
- Cleaned Poppet valve
I thought I might have a lean mixture problem, so I ran the boat this weekend and adjusted the fuel screws to a very rich mixture (4 turns out from closed). Still had an overheat.
Last night I removed the head covers and heads and inspected cooling passages. Everything looked pretty good for a 14 year old motor. No significant blockages.
The impeller has less than 8 hours on it, and the tell-tale is streaming water at full strength. Everything seems to be just as it should be, but I am consistently getting the overheat and limp mode after 5 minutes of operation at 4000 rpm. Allowing the engine to idle for 10 to 20 seconds will cool the engine enough for the alarm to turn off.
Anyone have any ideas of what the problem might be? I am totally stumped.
Rob
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