yet another470 merc ?

[marty mcewen]

i know the subject has been discused severely, but i feel im still in the dark.i have an 1980 merc 470 .it is stock as far as i can tell (no alternator or manifold changes). ihave owned it for 3 years and always take it to be winterized as we only get to use it for 3 or 4 months out of the year.it has never wanted to run on regular gas,and now the last few times we have taken it out we have noticed that it gets hot after towing skiers for awhile so we just rest and let it cool down, but i have noticed some antifreeze in the bildge when we pulled the plug when we got out of the water ,and it is loosing antifreeze from the resevoir, where do i start looking or what should i do. i like the powerof the motor and love theboats reliability, can i fix or should i sell?????

 

[jerryjerry05]

Re: yet another470 merc ?

You didn't include any maint history.How old is impeller? Has the riser/resivoir ever been changed? Has anyone ever changed the antifreeze? A 1980 makes that antifreeze almost 30 yrs old.Has anyome pressure tested the heat exchanger side? Let us know.Jerry

 

[marty mcewen]

Re: yet another470 merc ?

being a novice at boats, I have taken it to be winterized every year and I think they change antifreeze then? as far as impellar I havent changed it since ive owned it (3 years)every thing on motor looks original exept plastic expansion tank, looking at what i can see with radiator cap off it looks clean,when it comes to cars and motorcycles i can keep them going ,but when it comes to boats i,m lost, not evensure what riser /resevoir is,with a point in the right direction i can fix it just dont know where to start??

 

[achris]

Re: yet another470 merc ?

Most common cause of overheating on 470s is a clogged up heat-exchanger. Remove it and have it properly cleaned by a radiator specialist.... The source of the coolant in the bilge could just be overflow from getting hot.... While you have the heat exchanger in the shop, pull the lower unit off and service the water pump impeller....

Got a manual for the engine? If not and you want to do your own work, buy an OEM manual, not the after-market rubbish....

Chris..........

P.S. The heat exchanger is a black tube about 18" long and 3" diameter, directly below the exhaust manifold.... Acts like a radiator, but in place of cooling air on the outside it has seawater. The 'old' seawater is dumped out through the exhaust elbow.... big roundish bump at the back of the exhaust manifold.