Merc 50 casting around crank broken,

[Grant Manning]

Not sure of component terminology. Fuel/oil mix device (botton one) around crank has disintegrated. Could be due to worn bearing? Has made contact with crank web and blown apart. Bits found their way into cylinder bore. All main bearings and con rod bearings apprear worn. Will attempt rebuild but any help from you guys would be gratefully received.

 

[OBJ]

Re: Merc 50 casting around crank broken,

Hi Grant.....sorry ta' hear about the blow up.<br /><br />The "device" your referring to is called the reeds and reed cages. The are actually just one way valves that let fuel into the cylinders and keep pressure from blowing out the carb throats.<br /><br />Don't think damage is from a bad bearing unless it failed totally. Unually, reeds fail from age.<br /><br />Can ya' give us an idea as to the age of the engine and a little more info on number of cylinders?<br /><br />Failed reeds will cause damage to cylinder walls so if you do plan to rebuild, make sure the damage can be cured with honing or boring before you start buying parts.<br /><br />And a service manual would be a dandy thing to have around also.<br /><br />Thanks.

 

[andrewkafp]

Re: Merc 50 casting around crank broken,

Grant's Merc is a '76 50Hp. There are a few outboard wreckers around Aus if you are needing parts at a good price Grant..

 

[Grant Manning]

Re: Merc 50 casting around crank broken,

Have now totally striped engine. Reed valve casting seems to have broken off of securing bolt and then waggled around for a few thousand revs. One bore is scored and a piston is shot. Managed to buy an original manual from Caloundra Marine here on the Sunshine Coast. $30 aud. Steve at Caloundra said he can get a rebore done and supply parts. Should I try some wreckers first Unicorn? I don't want to go to all this trouble with second hand parts.

 

[andrewkafp]

Re: Merc 50 casting around crank broken,

Grant<br />I live in Melbourne... But took the boat up to Pumicestone Passage Caloundra last month..<br />Love the place.. <br />You have a 1976 motor.. You might weigh up the cost of rebuilding or buying a good used Merc of similar vintage and swap parts around. New parts are very pricey, escpecially the non consumables like pistons, reed valves, carbies and the like. There are quite a few old Mercs being sold in the Trading post (www.tradingpost.com.au).

 

[Grant Manning]

Re: Merc 50 casting around crank broken,

Unicorn. After haning around for a week waiting for quote from Caloundra guys I have given up and collected block, crank and pistons. I know I need a couple of pistons and will replace all bearings. Have not measured bores yet. Is it best to replace liners or rebore? We also use Pumictone as well as Noosa River. Do you email address?

 

[Grant Manning]

Re: Merc 50 casting around crank broken,

Unicorn. After hanging around for a week waiting for quote from Caloundra guys I have given up and collected block, crank and pistons. I know I need a couple of pistons and will replace all bearings. Have not measured bores yet. Is it best to replace liners or rebore? We also use Pumictone as well as Noosa River. Do you have email address?

 

[Clams Canino]

Re: Merc 50 casting around crank broken,

It's best to re-bore. Re-sleeving a block is reserved for totally catastrophic liner damage.<br /><br />-W