Re: Heat Soak fix (djarrett)
since you have a '91,the first of its breed, see an established dealer and ask them to recalibrate the carb throttle bodies per a service letter that came out for that problem back in about'93 or so. It showed the tech how to remove the core plugs and drillout a particular calibration hole about .002" larger.
Actually the letter was for "traileritis" where the motor would bog down while powering on the trailer. It also helped with heatsoak to get the motor running better when the fuel was vaporizing due to heat.
Re: Heat Soak fix (djarrett)
I have the same motor. I've fought "heat soak" since it was new. Mine would run OK until hot weather and then would run and idle good the first run of the day. After setting a while it did not want to idle and sometimes would stall out and die. It never wanted to push the boat up on the trailer. I missed the letter Seahorse told you about, so my motor has never been modified. I noticed that mine would idle fine all day, but die out when I put it into gear. Pushing in on the key to give it a prime would make it idle in gear for a minute or less. I thought it was a fuel problem and it might have been. My quick start started to take a long time to cut off and let the motor idle down, the thermostat was stuck open. I replaced both thermostats, and the quick start works fine. I raised the idle timing so in gear the idle would be around 800 RPM. I finally gave in and replaced the QL77JC4 plugs that came in the motor with the QL78YC. The purpose of this long post is that for some reason I now have no "heat soak" problem, the last three times out in 100 degree air and 92 degree water I have had no problems. I don't know what the hell fixed it or if it will last, but for now I'm a happy camper. http://www.bassboatcentral.com/smileys/smile.gif I think I would do as Seahorse said in his post and try to keep the idle up.