Hi, I really appreciate everyone taking the time to respond.
Are you running this motor on land (muffs or bucket?)?I am running this from the boat ramp while still on the trailer. I understand there are some intakes that require taping if using muffs. I don't trust tape, so I'm running the motor with it submerged in the lake.
Does the motor SEEM hot to touch? I had the cover off while I test ran the motor. While I did not touch the motor, I did not feel any excess heat. I did feel the pee stream when I first started the motor and it was strong flow and cold at both idle and 2,000 rpm. When the motor started the limp mode I felt the pee stream and it was not cold but not hot either, say luke warm.
Maybe steam from the exhaust port? I did not see any steam from the motor anywhere.
Is this motor being run in salt water?No. I bought this boat from a gentleman who said it was only run in fresh water and did not have many hours on the boat/motor. When inspecting the motor it looks almost brand new. I have not found any signs of salt water usage or salt residue. It was in a storage unit when I purchased. I suspect it may have sat for a while. We took it to the lake, launched the boat, it ran fine for 15 minutes up to 30mph and loaded it back on the trailer. no problems. I brought the boat home by highway about 2.5 hours. Then this issue started.
Was the inside of the thermostat housing all crudded up? No. I suspected the thermostat was sticking when the limp mode first started, so I purchased a Honda thermostat for this motor S/N and gasket and replaced. The housing was really clean.
Have you checked your fuel filters?I have checked both filters. Cleaned out the low pressure filter and replaced the high pressure filter. The high pressure filter was a light to medium brown and I found no debris in the filter.
Do any of the gas line fittings appear to be wet, like they may be leaking?I found a small wet/leaking fuel line, fuel tube B that connects between the low pressure filter and the low pressure fuel pump. I replaced this fuel line with a new one and new clips. I watched this fuel tube on the last test run. No leakage. I observed no leakage at the low pressure fuel pump connections either.
What does the primer bulb look/feel like when the motor drops rpm? Soft, like half full. Not hard/firm. I suspected this might be a problem with air leakage, so I replaced the fuel tube and bulb between the fuel tank and motor.
Is it still firm, collapsed, or soft? Have you tried using it to see if your rpms pick back up? No. I only checked the bulb midway during the test run and after the engine died and would not restart. The bulb was not ever firm, but soft and it felt like some fuel in the bulb.
Has the VST been apart recently? No. I'm trying to determine next steps and taking the VST apart for inspection is one item on the list.