Taking the new to me 1986 Mercruiser 470 out this upcoming weekend any advice ?

[tinydog]

1st trip out next weekend with this boat and 1st inboard. Bought this from a charity auction and fairly certain the motor is about shot. starts and sounds good on the muffs but seems to have alot of blow by but no smoke thats noticable from the exhaust but you can see it puffing at the breather and actually drips some oil from the tube at the arrestor. without having a compression tester I changed the oil filter, added straight 30w oil and a can of risolene ring seal and we will see if Im buying a motor or not. Is it possible that this engine could have sit enough for the rings to stick and maybe running at speed could free them up ? If not anyone got a good 470 for sale at a reasonable price ? Come on now give me a break ! I know I left some of you an opening with that last statement.

 

[a1nowell]

Re: Taking the new to me 1986 Mercruiser 470 out this upcoming weekend any advice ?

tinydog,
Welcome to the forum.

first of all you will hear a lot of bad thing about the 470, it's the strangest engine that Mercruiser ever made. There are several things you need to watch for on this maiden cruise.

1) DO NOT LET THE ENGINE OVER HEAT! Not over 200 degrees, and that is tooo much!
2) WATCH YOUR VOLT METER you should be reading 13.5-14.5 volts, if less you probably need an altenator conversion. You'll need one sooner or later.
3) Listen to the engine, run it thru a series of variable test runs increasing the RPM each time. (max RPM about 4400-4600) Watch for water leaks in the engine compartment.

This is a powerful 4 cyl engine and if you have no major machanical problems you should be good to go and repair.

There are a bunch of 470 owners on this forum. Just present your problem and you will get great answers.

Good luck on the maiden run,
Larry

 

[billbayliner]

Re: Taking the new to me 1986 Mercruiser 470 out this upcoming weekend any advice ?

Per your thread title and the fact of the 470, I'd say ask another working boat owner to tag along with you for the day.
Make this a shake down run, and leave any family and kids behind.

 

[Mikeymagoo]

Re: Taking the new to me 1986 Mercruiser 470 out this upcoming weekend any advice ?

My first time out I bent a pushrod and broke a rocker arm. We limped in on 3 cylinders. I've read that these engines will get you home, even with issues. Good luck!

 

[tinydog]

Re: Taking the new to me 1986 Mercruiser 470 out this upcoming weekend any advice ?

Finally took her out today ! Ran it hard with frequent stops and restarts. Man the 470 must have been a horse in its day because with 26 years on her and carrying a full tank of gas and three people that thing will jump on plane and do 46 mph @ 4000 rpms like nobodys business. Oil pressure stayed around 60 @ full speed with temp hanging around 140 to 160 but the water is still pretty cool here and charging system hangs around 14 to 16 volts. But I did have a small puddle of antifreeze at front starboard but oil stayed clean so after a few more trips to make darn sure all is going to stay well I will be doing the water pump seal project, Any volunteers with experience ??