? for powerhead guys

[rustyh]

got a 1982-83 basstracker with a 40 hp mercury 2 stroke 2 cylinder motor
6140511 serial, any way just got it back from tracker marine and they say no vacume to fuel system.. i am thinking reeds or rings but i have great compression and have tested fuel system to see id pump is working and as far as i can tell i am getting fuel in carb but not inside block i have rebuilkt all systems with th eexception of internal stuff such as reed block pistons connecting rods.....any other advice or diagnostic check to use before opening up block would be greatly appreciated

 

[crem1]

Re: ? for powerhead guys

Check out the reed valves

 

[rustyh]

Re: ? for powerhead guys

just an update i got some help from faztbullet and found out the ridges on the reed block were worn down so it does not have a good seal got a reed block from him installed new rigngs while i had pistons out and now runs like a champ .....just fyi you would never find this with out takeing the reed block off the reeds themselves looked to be in great condition .......also had great compression on the cylinder side but no fuel pump pressure.....with that being said it was very hard to diagnose and i also understand this type of reed block was used on motors from 35 hp up to 115 hope this helps some one out ........ps all those ridges are on the inside around the crank

 

[achris]

Re: ? for powerhead guys

Those ridges are designed to fill with oil and form a labyrinth seal around the crank to isolate the crankcase area of each cylinder. When they are worn the oil can't 'take up the slack' and they leak.... Causes all sorts of problems which are difficult to diagnose...

Chris.....