Engine stalling at idle

[saboga]

We are in the process of buying our new boat, and during the sea trial with the owner, he told us that the port engine will occasionally stall, which it did a couple of times. It tends to happen when the boat is moving forward at idle and you put the engine in reverse. If the boat is moving slowly it won't happen, but once the boat starts moving along, it will. It never happens with the starboard engine.

Is the solution just to tweak the idle up a bit on that engine? The boat has Cat 3208s with 4,400 hours. Both engines and transmissions passed the mechanical inspection and oil analysis, so I don't suspect there's anything wrong with the engine.

This is my first 'big' boat with 'big' engines, so I am new to this.

 

[Ski in NC]

Usually no big deal. My Cummins 450 will do it if I go directly to rev from fwd and boat has some forward speed.

Do check idle rpm. On some 3208 boats if idle was at 550-600 they would stall occasionally. On one it really bothered the owner so I set it up to 650 and problem was gone.

The rpm needed to prevent a stall depends on how big the wheel is, gear ratio, clutch engagement speed, governor droop, etc.

Not all governors are identical, been on a few twin engine boats where one would stall, one never would, even with idle rpm equal.

If engine checked out ok, I would not worry about it.

 

[Comodave]

Welcome aboard.

 

[bayview]

ON my Cummins 450C stalling on shifting was caused by a bent injection pump rack rod. Adjusting the bumper spring did not fix the problem neither did using a stronger bumper spring.