Should I not adjust my spark advance?

[schmoedog]

First i want to thank everyone for thier help on my T&T. I have a 1978 Merc 115. I have little power. Should I not adjust the spark advance cheater looking screw? if not how do I get any speed from the motor? I basically can get up to about 10 MPH on a 16 foot boat. Any thoughts? Also what do I set my new Teleflex amega tach for this engine? Imean what position do I set the dial on the back? Thanks already, because I know some of you guys have the answers.

 

[BKool68]

Re: Should I not adjust my spark advance?

Start off by checking spark and compression on all cylinders. with the motor running on muffs or in water pull one plug at a time to see if any produce no change (no change = no power). You are not making power in at least one to be going that slow. If spark and compression check out even across all cylinders then look at your carbsor fuel delivery.<br />good luck

 

[mrm]

Re: Should I not adjust my spark advance?

I have a 1981 115 merc. It started running very bad-- no power under a load. I removed the idle stablizer, then advanced the idle timing to 3 degrees btdc. Had the prop reworked and rehubed.<br /> I have only had this boat and motor for 6 months. It has never started or run as good as it does now. As soon as my son bring back my GPS. I will test my top speed. I think I will go faster than my old top end of 55 mph, with 2 people in the boat.<br /> I don't know if this will help your 78 model, don't know if it's set up the same way.<br /> MRM

 

[ODDD1]

Re: Should I not adjust my spark advance?

Schmoe, messing with that screw is the LAST thing you should do...comp test, spark test....you got cylinders not producing power, you want to overwork the ones that are running an wreck them too? fix whats broke, proper troubleshooting will tell you what is broke...playing with the advance screw will just add one more junk engine to the pile....