1972 evinrude 85 hp starflight!

[JOEjones31989]

ok i have a 72 85 hp electric shift starflight motor on my 16' boat. i just swapped props on it and took it out. me and my GF was cruising at WoT doing about 32 MPH. and all of a sudden it felt like it grabbed another gear and threw us back in our seats as it took off down the lake bad out a hell. i was suprised and impressed at the same time the GPS was registering 37 MPH it ran like that for another 30 mins or so back and forth as we was going from spot to spot on the water. the next morning i took out her brother and his son. we took off and the boat would only do 34 MPH again. but i couldnt hear or see any change in the RPM. then this morning we took it out to get our jugs and trotlines and it would start off at 33 MPH and after about 7 mins into the ride it would slowly drop down to 29-30 MPH but no change in RPM that i could tell. i heard a mechanic saying something about a spring or something under the flywheel i should check. can anyone elaborate on that for me please i have already cleaned both carbs and put new gaskets on it, i have replaced the fuel pump, i have ran a compression test on it about 2 weeks ago and the test came back with all 4 cylinders running 114-118 PSI. what do yall think or recommend?

 

[F_R]

Your mechanic may be correct. Or maybe not. Either way there are several ignition parts under the flywheel which could be the problem. Most likely are the breaker points. They may need cleaning and resetting. This is a normal maintenance item. Related to that is the spring he mentioned. There is a silver wire spring called a reverse cut-off. It prevents the motor from running backwards (yes it can run backwards). It rides on the crankshaft and requires regular re-lubrication. If ignored, it gets dry and wears, forming a powder of silver dust which fouls everything.

Bottom line: The flywheel needs to be removed and ignition system serviced if it hasn't been done lately.

 

[gm280]

Before going too crazy into tearing the engine apart, verify your prop isn't spinning or having any issue with the center rubber section... Just saying...

 

[racerone]

Yes , but that ignition system requires regular maintenance as per post # 2 above.---Ignoring that advice is not prudent !!!

 

[JOEjones31989]

i had plans on taking off the flywheel either this week or weekend but gotta wait for my dad to get in since all my tools are stored in his shed ATM, and i dont have a socket that big in my oh crap box. but i will deffently look into all the things under neath it. i got the boat a few months ago and been doing things here and thier on it but im pretty sure the flywheel has never been taken off, most the parts on the motor looked original, and previous owner had it sitting in a garage for the past 3 years.