Lehman 225 high idle only even warm?

[Steve91T]

Hello all. My new to me boat has an odd issue. The idles when cold are 500-600. The starboard ending actually shakes at cold idle, as if the idle is too low. I usually bump the throttle up just a hair when cold to calm it down. I usually let them idle for a 5 minutes or so before leaving the slip or anchorage. They never try to quit when going in and out of gear.

But once up to operating temp, both idles are right at 1000 in neutral, but drop to 700 ish in gear, but they clunk more than I’d like going in and out of gear.

I’m thinking of lowering the idle when hot and just dealing with a low cold idle.

Anyway, just wondering if this is normal to have such a difference between hot and cold idle.

Thanks.

 

[Comodave]

I am not a mechanic so I am not sure exactly how it works, but my SP225s have a cold high idle switch on them. Before I start them when they are cold I push the throttles full open. There is a push button switch that sets the high idle. I push the button, pull the throttles back to idle and start the engines. They idle at a higher RPM until they warm up. Works great. Not sure how to install such a system but you might try Brian at American Diesel.

 

[C lectric]

I'll second contacting American Diesel. Likely there is an adjustment for both the cold and the hot idle.
They should be able to tell you Just what is the procedure.