A recent report from Indmar, a manufacturer often associated with Supra boat engines, details an investigation into a concerning engine problem. This report sheds light on a specific case of engine failure, revealing potential causes and warranty implications for Supra Engine owners. The issue, reported by a customer, involved a severe lack of compression in one cylinder of their Supra engine.
Initial Problem: Zero Compression in Cylinder #3
The customer reported a critical issue: zero compression in the #3 cylinder of their Supra engine. This is a serious problem indicating a significant internal engine malfunction. The engine, taken to a dealer on July 8th after an incident on July 6th, was eventually received for inspection on August 4th. The delay in receiving the unit for inspection is noted but not explained in the report.
Inspection and Testing of the Supra Engine
Upon receiving the engine unit on August 4th, a thorough inspection was carried out to diagnose the cause of the zero compression.
Visual Inspection Findings
The visual inspection immediately confirmed the customer’s report and revealed further damage:
- No Compression on #3 Cylinder: As reported, cylinder number three exhibited no compression.
- Melted and Breaking Piston #3: The inspection revealed that the #3 piston was not only damaged but had begun to melt and break apart. This is a clear sign of extreme heat and abnormal combustion within the cylinder.
- Engine Details: The engine registration and sale date was recorded as June 26th, 2020. Crucially, the engine hours were logged at just 121 hours, indicating a relatively young engine experiencing a major failure.
To further investigate the root cause, a limited tear-down of the Supra engine was performed.
Limited Engine Tear Down Results
This deeper inspection provided more clues:
- Injector #3 Within Specification: The fuel injector for cylinder #3 was tested and found to be operating within its specified parameters. This suggests the injector itself was not faulty and delivering an incorrect fuel mixture.
- Water in Fuel Sample: A fuel sample taken directly from the fuel rail revealed visible water contamination mixed within the gasoline. This finding became a critical point in determining the cause of the engine failure.
Summary and Conclusions: Fuel Contamination as the Likely Cause
The Indmar report concluded with a summary of the findings and a determination of the likely cause of the Supra engine failure.
- Piston #3 Melt and Breakage: Confirmed as a result of the inspection.
- Injector #3 Functioning Correctly: Ruled out as a direct cause.
- Water Found in Fuel: Identified as a significant factor.
- Lean Engine Operation Due to Fuel Issues: The report states that excessive water in the fuel, or potentially low octane fuel, would cause the engine to run “lean.” A lean fuel mixture (too much air, not enough fuel) leads to increased combustion temperatures, which can cause pistons to melt and break down.
- Warranty Exclusion: Indmar’s warranty explicitly excludes damage caused by using unsuitable fuels or lubricants, including fuel system components. Therefore, damage resulting from fuel contamination is not covered under the Indmar Limited Product Warranty.
- No Manufacturing Defects Found: The inspection found no defects in workmanship or parts within the engine that could have caused this failure.
- No Other Root Causes Identified: The report concludes that no other potential causes for the engine damage were found besides fuel contamination.
Misfire Alarm History
Adding another layer to the situation, the report mentions a recorded misfire alarm at 112 engine hours. While the customer was informed of only one misfire alarm, the engine data apparently showed 6000 misfire alarms. This significant discrepancy was not communicated to the customer and only came to light after the engine experienced severe smoking and went into limp mode while returning to refuel. This alarm history could have been an early warning sign of the developing engine issue.
Final Assessment
In conclusion, the Indmar report strongly suggests that the failure of this Supra engine, specifically the melted piston in cylinder #3, was caused by water contamination in the fuel, leading to a lean running condition. This type of damage is explicitly excluded from the Indmar warranty, leaving the owner potentially responsible for the repairs. The unreported history of numerous misfire alarms also raises questions about preventative maintenance and early detection of engine problems. This case serves as a crucial reminder for Supra engine owners about the importance of fuel quality and regular engine monitoring.
