1250 test results on the water and question about pitch

[69GlassparMan]

Okay, After tuning Idle I have it about perfect. I took boat out on the salt with a couple buddys to try the new power trim unit I installed. Well boat started right up and after warming I put down fast idle arm and idle good at about 800 rpm. Still have adjustable propulse prop set on 18pitch. Took off and boat was right on plane! steady ride at about 30 seconds to WOT at about 30mph on salt water. Then I tested power trim tilt. My GPS died but It appeared that we gained even more WOT upon putting trim out or motor up and front bow up some. It felt like possibly 34-36 mph in this 1969 17ft 1000lb Semi V glasspar citation. VERY IMPRESSED with this motor. Did not run hot and idle was fairly smooth for a 2 stroke. <br />Question. Do you think my pitch is correct. I can set this 4 blade composite prop from 15-20 pitch. .<br />One thing that sucks. I was using my minkota trolling motor in reverse to keep a line straight in current to fish. Upon leaving I noticed my trolling motor only goes in reverse now. Forward and prop does not move,.<br />??? thanks

 

[2cycle]

Re: 1250 test results on the water and question about pitch

Originally posted by 69GlassparMan:<br />[QB] Question. Do you think my pitch is correct. I can set this 4 blade composite prop from 15-20 pitch. <br /><br />Your proper pitch will be determined by your WOT RPMs under normal load. Prop it to make 5500 RPMs to avoid "lugging" as these inlines are sensitive to detonation issues. Also make sure your max spark advance is set at no more than 21 degree BTDC. <br /><br />I'm a little jealous. Yours idles down a little lower than my 1500. I can only get about 900 on a good day. Sounds like you've got yourself a good one.

 

[Clams Canino]

Re: 1250 test results on the water and question about pitch

Umm.... the 1250 is the last of the cross-flows begore the detonation prone engines began in 1970. <br /><br />Correct to prop it to make 5500 at WOT, but max advance on the 1250 is 34 degrees as opposed to the 21 mandated for 1970 and later inlines. And use mid-grade gas.<br /><br />-W