used engine checklist

[captkid]

so I am looking at a used Mercruiser 470... the engine starts right up idles no problem, and seems to run great... the guy selling it is doing so cause the boat itself is junk, floor rotten, so is the transem.<br /><br />my question is what should I be looking for when buying a used engine? ... <br /><br />here is what i do know...<br /><br />charging system works (original fact. one)<br /><br />oil pressure was at 30-40 when at a warm idle and got up around 50-60 when reving high rpms, the engine wasnt at operating temp yet thou<br /><br />temp seemed good (we had it hooked up to muffs)<br /><br />there was no water in the oil, I checked b4 he started it and after we ran it for about 20 mins<br /><br />no water leaking outa the front seals (YET )<br />or anywhere for that matter<br /><br />the engine itself was very clean<br /><br />the guy was an old mercruiser mech. and i felt comfortable dealing with him. he is looking for $600 for the engine, and offered to throw it in my boat for an extra $100 if I didnt want to mess w/ it. it all sounded like a good deal to me.<br /><br />what do u think?<br /> <br />thanks as always<br /><br />kid

 

[Bondo]

Re: used engine checklist

Sounds like a Great Deal..............<br />A Compression,+ Leak-down Test will give you a Pretty Good indication of the over-all condiction of the motor......<br />What happened to the 1 you were Rebuilding ??????

 

[captkid]

Re: used engine checklist

What happened to the 1 you were Rebuilding ?????? <br />

I decided that rebuilding my other motor will be my winter project for this year <br /><br />and I figured this engine i can bolt in and go, plus probably never hurts to have a spare engine kicking around <br /><br /> Bondo hey man what is a leak-down test?<br /><br />but yeah it sounds like a good deal to me also.... thats why I am asking you guys...

 

[TwoBallScrewBall]

Re: used engine checklist

plus probably never hurts to have a spare engine kicking around

AMEN to that my brother!

 

[POINTER94]

Re: used engine checklist

What does it mean when you have high oil pressure? I am running over 70 when at idle? Doesn't change much at cruising speed. Bad sensor?

 

[Northern Eclipse]

Re: used engine checklist

CaptKid a leakdown test is a test using compressed air and a air fitting with gauge setup, that you screw the sparkplug hole, make sure piston is TDC on compression, that means both valves closed, and let few pounds of air into cyclinder, and listen for air leaks, If you hear air coming up carb, intake valve not seating, hear air in the exhaust, valve not seating or broken, hear air coming from oil pan, bad rings. If you have closed cooling and get air bubbles in the coolent tank, possible head gasket failure, this type of test is normanlly done if you found a cylinder low on compression after a compression test, the leakdown will help determine why you have low compression, you can also use that compressed air to hold the valve's up while you change valve spring and retainer, without removing the head, but only if you pass the leakdown first.

 

[doman]

Re: used engine checklist

What does it mean when you have high oil pressure? I am running over 70 when at idle? Doesn't change much at cruising speed. Bad sensor? <br /><br />i belive you have a faulty oil pressure switch if its not changing during wot or idle <br /><br />Dom

 

[captkid]

Re: used engine checklist

this type of test is normanlly done if you found a cylinder low on compression after a compression test

what is considered low... I have read 140-150 is a good range, but what would be low... <br /><br />the other questionalbe thing is i dont really know the number of hours on the engine, neither does the seller, but i guess if compression is good the number of hours really shouldnt matter?<br /><br />kid

 

[xlr8n4fun]

Re: used engine checklist

"there was no water in the oil, I checked b4 he started it and after we ran it for about 20 mins" <br /><br />... How do you tell if there is water in the oil? ...

 

[captkid]

Re: used engine checklist

... How do you tell if there is water in the oil? ...

really the only way I could check was pulling the dip stick... i guess I coulda showed up with a few quarts of oil and a filter and pulled the old oil but the oil looked good on the stick...

 

[boatguy19]

Re: used engine checklist

one of the problems those motors have is the camshaft the end of it goes bad and they start leaking water out of the weep hole, can be fixed with a sleve but usually dontlast long thats just another thing to look for good luck

 

[Northern Eclipse]

Re: used engine checklist

Captkid Compression 140-150 would be good, but its more important that the readings are close to even across all cylinders, such as if you had a motor that was say 140 145 90 140 I would be concerned with No3 if I had say 105 115 110 110, I would suggest compression is low but even, if its still running good I wouldn't be worried, but it would suggest the motor is getting tired, if you see reading below 125 across all cylinders it starting to head to the low side but thats not to say its to low ,110 115 now thats getting low for me. But from the condition you describe that motor to be in so far its a good buy, and If he will Install is for 100 bucks its well worth it, heck you could part it out and get money back out it.