checking 300x before purchase

**Tranq** · 08-12-2019, 02:47 AM

Found a 2005 motor with 100 hours declared. What should i do?
Firt of all, compression. What good number (130+ psi?)? Then, сonnect Mercury terminal, what i can see?
And what another things i should check?

**R.grover** · 08-13-2019, 12:51 AM

Compression and cylinder leakage test.
Check out the oil in the lower unit. what lower unit is it got on it?
What trim system dose it have?
What type of use are you using it for?

Find out when the last time the fuel injestors were flowed and cleaned.
Have the heads been off and new orings fitted?
Reed valves have they been replaced? Do be prepaired to have to put new reeds and fix/blocks in these motor the rubber coating burns.

**Tranq** · 08-13-2019, 01:49 AM

Nothing never replaced. Only 100 hours. Should i need replace reed valves and head o rings? What are you mean about "rubber coating burns"?

Motor with sportmaster, 20 mid, bass trim. But a have 2000 300 pro max offshore trim and bracket and can install 300x head and mid. Motor is for 23ft deep-v, copy of Phantom 23, pleasure boat, not only for racing.

**R.grover** · 08-13-2019, 02:53 AM

Maybe only 100hours but its 14 years old.
Reeds go hard and dry then dont work correctly.

**R.grover** · 08-13-2019, 03:01 AM

top pick with rubber on the cauge lower pick it a type with rubber removed.
New blocks are around $360usd each.

If it was my motor from what i have seen on these motors id be doing as lissted below.
Compression test. cylinder leakage test.
Check gear oil for water and burnt oil. Check propshaft if its bent and splines ok.
Check trim oil and shafts and seals ok.
Down load ecm to see where the engine has sat in rev range.

Then when i own it then i do the list below.
Head orings.
Thermostats and popet valve.
Reseal lower unit and replace oil.
Replace all engine oil and bleed hoses.
Replace reeds and fix/replace reed blocks.

Ive owned 13 of these for my own boats.