suzuki 1987 75hp outboard overheating

[hockings]

Suszuki 75hp outboard is overheating WOT. Tried repacing headgasket,impeller,checked overheat sensor (OK), pulled off powerhead and exhaust covers to check for blockages,none found...This motor is on a 24' Weeres pontoon. We've also tried running it without the thermostat, didn't overheat but running hot on #2 cylinder.<br />PLEASE HELP!!! Why is it overheating????

 

[Fouled Plug]

Re: suzuki 1987 75hp outboard overheating

Is the alarm sounding? How are you measuring the temp on #2? Correct heat range plugs in the motor? The thermostat belongs in the engine, but I'd replace it if it fails the stove-top test.

 

[Bear]

Re: suzuki 1987 75hp outboard overheating

Are you sure the prop is right for WOT on a pontoon? Do you see like 5500 rpm or is it under 4000?<br /><br />Just a thought.<br /><br />/Bear