250 inline 6 - Break-In

[Will Fish]

So I've got the boat in the water after a new motor install and a few hiccups. Motor running nice and smooth and I now have 10 hours on the break-in. Time to change the oil and make some fine tuning adjustments.

I've noticed one problem maybe you guys can give me some insite. At a cold start, she cranks right up without the need to give it gas. However, while warming up, I can smell the fuel burning and real rich. Once running for a while and warmed up, if I turn the engine off and try and start it again, she's starving for fuel idling at about 300-500RPMs and will stall out. I have to give it gas to bring the Idle up and then she's fine. What adjustments can I do to not run so rich but still be able to start without stalling when warmed up. I do not want to increase my idle because I think I'd be idleing too high at cold start and running even richer than I am now.

 

[Oshkosh1]

Re: 250 inline 6 - Break-In

I'd hook up a vac gauge and "tweek" the F/A mix. Check the choke plate after it warms up as well. I'm assuming you have a Rochester 2bbl on it similar to my setup so set the idle speed to about 800RPM if you're on muffs. It seems a little high, but when you drop it in the water, the backpressure will bring it down to around 600/650 RPM.

 

[Will Fish]

Re: 250 inline 6 - Break-In

The boat stays in the water till late fall so I'd set the idle to 650ish, which is where she's at on cold start. I'm leary about setting the idle at 650 when shes warm cause it would be too high at cold start. Yes it's a Rochester 2bbl. I have to check the choke and maybe make an adjustment. Where would I connect a vacuum gauge to? I have one on my dash, but has never worked.. Lol. I've always been more concerned with temp and oil.

 

[Oshkosh1]

Re: 250 inline 6 - Break-In

On top of the manifold, just aft of the carb is a port to screw the gauge into.