2000 Yamaha 200 HPDI Overheat Alarm

tanklab

Recruit
Joined
Nov 27, 2011
Messages
1
I am having a problem with the engine overheat alarm (digital guages) sounding on one of my 2000 Yamaha 200 HPDI engines.
The problem seems only to occur at higher RPMs (>3,500)
The first time I experienced the problem the port engine was running rough (lots of vibration) and was having trouble reving up beyond ~ 3,000 RPM (RPM reduction mode?). Then on the way back from our run out to the engine alarm sounded.

The second run I was able to run the RPMs up beyond 3K, however I do recall that the port engine took a lot more throttle than the SB to get there. I was very rough that day, so this is not a precise analysis.

On the last run I first tried to get the boat up on plane the port engine would not rev up beyond 2,500 to 3,000 RPM (no alarm sounded). I shut both engines down and re-started and then was able to run up to 5,000 RPM for a while. After a few minutes running at 4,700 the engine alarm sounded again.

Listed below are the items I have addressed:

1. Thermostats- replaced
2. Pressure relieve valves( poppet valve)- replaced
3. Water pump impeller ? replaced
4. Heads removed and water jackets checked - clean as a whistle!
5. Replaced fuel filter cannisters (Raycors)

Given the above repairs, it does not seem that it is a cooling problem. Could it be a problem with the oil injection?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: 2000 Yamaha 200 HPDI Overheat Alarm

I would think it is a fuel problem. These motors run on the very edge of lean and any plugging will cause a lean condition that will eat pistons.
Check compression on all cylinders to make sure you have not damaged anything already and keep a record for later reference.
then monitor fuel pressures and clean/ replace all of the screens and filters.
there are multiple ones in this fuel system.

Did you replace just the impellers or other parts also?

When was the last time you cleaned and tested the oil system
 
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