Hey everyone,
First of all I've searched the archives and found nothing that explains my issue. 2nd I'm a marine mechanic, but mostly work on large outboards. This is my own boat for a HP restricted lake.
I'll note this ran fine all year (bought used in February) thru last Friday. The very next day, and immediately after starting from cold, I couldn't get WOT. This is on an underpowered aluminum bass boat with a (new) prop pitched the flattest I can (9.25x8) and only turn 4500 but usually get 14 mph solo. Now I'm getting 3,000 and 6 mph lol. Factory jet, OEM carb kit recently done, Champion L77JC4 plugs (already tried new ones as a fix), new fuel line, etc. Fuel is clean, mixed right, new water separator, and even dumped the tank and started over anyway to make sure. Compression is 100 on both. Didn't look into the fuel pump yet but suppose I should rebuild that anyway but that's not likely to cause exactly this below...
After realizing I had an issue, I noticed condensation only around the reed body and carb. The power head is dry. It was running for a while at this point so I felt the t-stat cover area and that seemed operating temp warm. I left the cowl off, trimmed it up and fished a while to let everything dry. Hours later I tried again. Same running issue, condensation came right back. The only difference between Friday when it was fine all day, and yesterday, was that it was rainy and pretty humid. But that shouldn't cause major running issues if everything with the engine is good. Cowl isn't cracked or anything, it's condensating itself with the help of ambient conditions. I know I need to pull off plug wires individually while running in water to see if I'm down a cylinder, which I'm sure I am. But that doesn't explain the condensation and it's a lot. Any suggestions? I have no reason to suspect the thermostat is stuck open and if it was, why would just the reed body and carb get damp?
First of all I've searched the archives and found nothing that explains my issue. 2nd I'm a marine mechanic, but mostly work on large outboards. This is my own boat for a HP restricted lake.
I'll note this ran fine all year (bought used in February) thru last Friday. The very next day, and immediately after starting from cold, I couldn't get WOT. This is on an underpowered aluminum bass boat with a (new) prop pitched the flattest I can (9.25x8) and only turn 4500 but usually get 14 mph solo. Now I'm getting 3,000 and 6 mph lol. Factory jet, OEM carb kit recently done, Champion L77JC4 plugs (already tried new ones as a fix), new fuel line, etc. Fuel is clean, mixed right, new water separator, and even dumped the tank and started over anyway to make sure. Compression is 100 on both. Didn't look into the fuel pump yet but suppose I should rebuild that anyway but that's not likely to cause exactly this below...
After realizing I had an issue, I noticed condensation only around the reed body and carb. The power head is dry. It was running for a while at this point so I felt the t-stat cover area and that seemed operating temp warm. I left the cowl off, trimmed it up and fished a while to let everything dry. Hours later I tried again. Same running issue, condensation came right back. The only difference between Friday when it was fine all day, and yesterday, was that it was rainy and pretty humid. But that shouldn't cause major running issues if everything with the engine is good. Cowl isn't cracked or anything, it's condensating itself with the help of ambient conditions. I know I need to pull off plug wires individually while running in water to see if I'm down a cylinder, which I'm sure I am. But that doesn't explain the condensation and it's a lot. Any suggestions? I have no reason to suspect the thermostat is stuck open and if it was, why would just the reed body and carb get damp?