Marinex
Veteran Member
My friend and I both own Grand Banks boats with the Lehman 120.
On his twin engine Alaskan one engine has an issue where it can only reach about 11-1200 RPM under load when traveling but stopped in neutral the engine can be revved up to 2000 RPM easily.
He thought he had maybe picked up something in the water and wrapped it around the prop so had a diver buddy check it out but both props spin freely and nothing was on the shaft.
We changed fuel filters and bled the system to make sure the fuel was not restricted and checked transmission oil levels and oil odor for any sort of issue.
The only other clue is that he says if he keeps running it at the low RPM the engine coolant temp starts to rise, that´s why he thought something was wrapped on the prop shaft.
The Exhaust color seems normal.
Any ideas on what to try next? Could it still be a fuel issue?
thanks, Andy
On his twin engine Alaskan one engine has an issue where it can only reach about 11-1200 RPM under load when traveling but stopped in neutral the engine can be revved up to 2000 RPM easily.
He thought he had maybe picked up something in the water and wrapped it around the prop so had a diver buddy check it out but both props spin freely and nothing was on the shaft.
We changed fuel filters and bled the system to make sure the fuel was not restricted and checked transmission oil levels and oil odor for any sort of issue.
The only other clue is that he says if he keeps running it at the low RPM the engine coolant temp starts to rise, that´s why he thought something was wrapped on the prop shaft.
The Exhaust color seems normal.
Any ideas on what to try next? Could it still be a fuel issue?
thanks, Andy