The Air is a Lot more Humid as the Polar Caps melt, and Weather will be getting More Extreme
That's 40C, and we had a few days like that 2 yrs ago, up here the Great White North. Brutal, then at Night, 100% Humidity.
I built an Ultrasonic Cleaner in the 70s, Heathkit
Various Automatic Chokes Systems were devised on some Engines by OMC during the 60s, by the mid 70s, they were discarded and the Solenoid Electric Choke, as used by others, became the Standard Electric Choke
My City
Where do you do your Boating?
Power Trim on these Motors has 2 Cylinders/Rams, and they are not Interchangeable
If it only has One, it has Power Tilt, not Trim
Until the Induction System warms up, it will need Spark Advance(that is what controls Idle and Low Speed on these 2 Strokes, not Carb Opening) and an Enriched Mixture to keep running.
Does the Accelerator Pump function?
Who rebuilt the Carb?
Were all the Passages cleaned properly?
Float adjusted correctly?
Float still buoyant?
All Internal gaskets in Carb correct, and installed correctly?
Orifices NEVER Wear out. They may Clog up with Dirt/Gum/Varnish, but they don't wear...
GM had an Oil Additive called EOS(Engine Oil Supplement). It was useful as an Assembly Lube and for Camshaft Break In protection. It was not recommended by GM for regular use as Compounds within it were Detrimental to the Cats(that alone would make me want to use it all the Time). In the 70s GM...
Someone was in there, scraping Carbon off the Pistons.
Dropping the Gear Case might reveal if it, or the Powerhead is the Problem. Odds of both being Seized are low.
The 3 cylinder 75hp is weaker in Holeshot than the 3 cylinder 70hp of the same displacement. That is due to the Port Timing to get the extra 5 hp.WOT range for it is 5200-5800, but that engine will run better and last longer if it propped to run as Close to 5800 as possible
I think you better start over. You stated the tires were St 215/75/13, yet the pics say St 215/75/14, which you later admit, in the Mean time you are saying one is a Spare...
Both tires in the Pic are Trailer Tires
Like I said, start over.
Back in the Days of Carburetors, and Fuel Pumps on the Engines the pulled Fuel from the Tanks, Vapour Lock was common on hot Days(Gets a lot Hotter under the Hood of a Car, compared to the Bilge/Engine Compartment of a boat) I would carry a bottle of Water that I would Pour on the Fuel Pump, and...
If it were going to Vapour Lock in a FI system, it would be between the Tank and the Lift Pump especially if there is a Filter in between, as that would be the only location that would have lower than Atmospheric Pressure. Downstream of that Pump the Fuel would be under Higher Pressure and far...
