Anyone have input on issues with these motors, or what to look for?

Looking to purchase a boat with twin Scorpions with around 370hrs.

Salt or freshwater?

Check codes.

Compression/leak down test.

Sea trial. Do motors pulled rated rpm assuming propped correctly?

It might be worth while to clean and flow test the injectors if you purchase the boat.

If taken care of with routine maintenance 370 hrs on a Scorpion motor should not be an issue.

Best of luck.

these were from Mercury racing. Dated ECM MEFI 3 compared to today standards but time period correct. EST ignition set up - Merc gen II cool fuel - electric fuel pumps can be issue. Outdated fuel injectors by todays standards and IMO somewhat dated for that timeframe.

Yes I agree with flow testing and checking the injectors before getting after it on the water. Also fuel rail corrosion and or aluminum oxcide material that can hurt the injectors really bad.

Water circ pump if older than 6 years old. check out the exhaust manifolds and risers - riser gasket seal can leak - if you see external water leak stains then possible internal water leaks.

I would 4 sure have a comp test and leak down test done. Scan engine. MEFI 3 really does not show that many fault codes but check total engine hours and run times per rpms. It is best to buy a boat that has ran majority of its run time at 70 to 75 % of its max duty cycle.

I plan to have a mechanic scan and complete compression tested, along with an over all look at the motors. The seller is sending me 14 years worth of marina service records to comb threw as well.

Water pumps were just serviced as well.

Thanks for the input, Im coming from an HP500 which obviously had it's issues, Just want to beware of what to expect from these motors.

I plan to have a mechanic check codes, scan hours and compression test. Also have 14 years of marina service records, sounds like boat has been cared for very well. Thanks for your input.

Mercury Racing is recommending top end refresh at 400 hours for these motors, anyone have any input? My blue 500 needed it due to the spring issues, but I can't seem to find any info on this subject other than these motors should be good for at least 800 before a rebuild. I would like to find out if anyone has performed this as preventative maintenance, and if so, what condition were the components in.

I would say at least have it looked at especially valve spring pressures and valve to seat sealing if all possible. Before that a leak down test would nt hurt.

It seems 500 hours depending how the engines have been ran, is the timeframe to get into the top end 4 sure.

Like everything, It all depends with on time proper maintenance beforehand and how hard the engines have ran. Like I said if majority of its engine runs times for the best longevity falls into 70 to 75 % of the engine max duty cycle, that always helps for any marine engine.

It should be fairly easy to check the top end but in my estimation these motors were/are more robust upstairs than the HP500 motors. 377s should be a good 800-1000 hr motor assuming they weren't beaten like a mule. They typically had better internals than the black motors.