MERC 500HP FACTS, FICTION, ????'S AND ANSWERS...

[bocco]

Does anybody know if there is much difference between the gen 5 and gen 6 motors besides the basic block. I'm sure mine is gen 6 due to the cast timing case cover. But the only Mercruiser service manual I could find only covers the gen 5. I'm curious if the same valve train parts were used.

 

[2FORCEFULL]

I would imagine that if you had 3 dead holes you'd hear it, and you'd feel it, Dry headers in a car, absolutely we check em with the infrared all the time during initial EFI setup and shake down, wet rag too is fine, hell even just getting your hand close you can feel if it is hot or not without even touching it. But on it's almost impossible to gauge runner temp on a manifold that is heavy walled aluminum surrounded by a water jacket wicking heat away by touching it. There is a ton of water flowing through there and the whole temperature differential is dampened by that. Depending on where the water is coming in from, and the flow through the manifold. I would never rely on that as a full proof method of telling whether or not the cylinder was firing in a marine application with a cast and common jacketed manifold.

damn Shane, gotta love your detailed answers...but, on the gils... you can feel the heat right where the manifolds bolt to the head...and yes you can here the miss... but everybody at the dock thinks you have some big ass cam nasty big block..what I did during the fist two trips out was run it at the dock at 1500 rpms.... you could feel the dead holes come to life, and hear the motor start to smooth out..the rpms would jump up to about 2000...the temp only gets to 125 degrees,,I would like to see more like 170....but even when warm... you had to peddle it when it went in gear as she would lay down and die...gonna blame that on the spark plugs flooding...I did a compression test, and no I didn't pull the motor and put it on the dyno....lol all the cylinders pumped 180LBs... and no I didn't do a leak down..what I was looking for was low compression in some of the cylinders... had I found that to be true, I would do a leak down....the way a motor works is air comes in the intake manifold. and out the exhaust....on a good running motor, a leak down will tell you how much air is leaking past the rings or valves...again, when I go to the lake..I don't bring the whole shop with me, and no how to check for fuel and spark, sooooo... I just came home as I found there to be problems..

 

[2FORCEFULL]

A few cheap inline spark testers will tell you if you are getting fire to the plug, and its not too difficult to see if said plug is firing.

My question is who and why were the plugs installed with an .022 gap ? This makes no sense at all ...
also , what became of the spaghetti steering lines and slop.

I just put some sauce on them....haven't got to pulling them and taking them to get shortened at the local hose shop..

got no idea why, but gonna guess they just pulled them out of the box and installed them... or they had a cub that thought he heard gab them to .025... who knows... but it was a easy fix, and I was glad to find that as it would cause what the motor was doing.... also.. the new correct plugs are longer and stainless...I'm gonna go run it , hopefully able to see what help the drive plate is.... I bought a -2 imco lower unit,.. hopefully won't have to use it.. I didn't buy this boat to go fast,.but, want it to work proper a any giv'n speed..we cruise around the 50 mph mark... and some times slower, or faster... just wanna be safe, go out my own power, and come back on my own power... thats a fun boating day

 

[Racey]

damn Shane, gotta love your detailed answers...but, on the gils... you can feel the heat right where the manifolds bolt to the head...and yes you can here the miss... but everybody at the dock thinks you have some big ass cam nasty big block..what I did during the fist two trips out was run it at the dock at 1500 rpms.... you could feel the dead holes come to life, and hear the motor start to smooth out..the rpms would jump up to about 2000...the temp only gets to 125 degrees,,I would like to see more like 170....but even when warm... you had to peddle it when it went in gear as she would lay down and die...gonna blame that on the spark plugs flooding...I did a compression test, and no I didn't pull the motor and put it on the dyno....lol all the cylinders pumped 180LBs... and no I didn't do a leak down..what I was looking for was low compression in some of the cylinders... had I found that to be true, I would do a leak down....the way a motor works is air comes in the intake manifold. and out the exhaust....on a good running motor, a leak down will tell you how much air is leaking past the rings or valves...again, when I go to the lake..I don't bring the whole shop with me, and no how to check for fuel and spark, sooooo... I just came home as I found there to be problems..

I always like to watch the "puff" on a compression test. the first bump of the needle. That tells a lot. Letting the the thing pump several times tells you less.. A little trick that helps save some time.

 

[guest hs]

Steve thanks for coming and seeing me today sorry I was so busy and couldn’t shoot the shit with you more.

 

[2FORCEFULL]

Steve thanks for coming and seeing me today sorry I was so busy and couldn’t shoot the shit with you more.

didn't think you were gonna get yur ass whipped or I would have stayed to get your back... you should have lay'd on the ground and acted like he knocked you out....lol

 

[Holymoses]

Steve after reading this thread I’m going to pull my 500efis and build both motors the have 475hrs so figure now would be a good time to run through them. I’ll run them till the end of this season then out they come I can’t see just doing the Top Ends or New heads and valve train and not knocking out the whole motor once out of the boat.

 

[2FORCEFULL]

Steve after reading this thread I’m going to pull my 500efis and build both motors the have 475hrs so figure now would be a good time to run through them. I’ll run them till the end of this season then out they come I can’t see just doing the Top Ends or New heads and valve train and not knocking out the whole motor once out of the boat.

Here's the real deal....the Short block portion will go an easy 1000 hours, and the top end on the 500 hp is an easy do in the boat..but I could see it being a pain if it was twins...boat mech's can pull those motors quick..so like you say... might as well pull the pans and check the rotating assembly.. the cool thing about doing that is you get to check the bores... nothing better that a seasoned block to build a motor...a lot will depend on driving habit's and size of boat...like racey say's you're always going up hill,... some things in life you never figure out, one for me, and I've known Racey for quite some time, is how the fuc did this kid learn so much and know so much at such a young age,... I love talking to the guy...but getting back to your boat and motors,.. I would do the aluminum heads, first just for the weight loss gain,.. on my 270 I went from struggling to turn a 24p prop to spinning a 26 with ease...never put it on a dyno. but man you could really feel the difference of the low and mid range torque....as for my boat... I think it is pretty spot on for what I wanna do with it.... yeah, you can always go "FASTER", but with my 210, I just wanna be able to cruise out to hallett beach at 50-60 mph without having to be on pin all the way..the 210 is an anybody drive boat to 70mph.... after that it becomes a drivers boat,... bad things could happen letting just anybody get behind the wheel..but, like I said before, it just bewilders me the amount of people that throttle these full race motor boats...that don't have a clue...when I raced blower motors...we ran the valves and checked the plugs every 1/4 mile...and still broke shit...

 

[2FORCEFULL]

one thing people over look on merc race motor, and even the bottom of the pile... the carbbed 500hp...the price of the motor package includes from the spark arrester to the prop shaft... so a 525 efi is a hell of a deal with an xr drive,.. a few yrs ago they could be had for 32k...that's everything you need included.. so doing an on time refresh, money in the bank..merc has a refresh program, you send them the motors, they go complete through them and come back with a 2 yr guarantee , probley a little pricey.. but , you have the worth a lot to the general public to boast that you have fresh merc repower...there a boat that been for sell for awhile. I think its a 30'r twin carson motors..the motors alone are worth twice the asking price.... but the general public doesn't know carson brumitt.. the perceived value to them is higher with merc... I owned quite a few boats in my day, although I'm not skeert of small shop builds...I've found most of the motors to bolted together pile of lies...the guys says... we only used the best part available...must of been what was available in his storage shed, as the rods and pistons didn't even match,.. they throttle like a double jointed woman, try to eat its self ever time out...I had a custom 598 built from cal..started the motor, got on plane , shut it down and idle back on the trailer..called the builder, told them the motor was gonna go.... ah bull shit was there reply... so I hauled it back to the shop...the motor builder was a cocky little fuc... and I knew how to play him...I said, I could have the motor out and pan dropped in less than an hour, and I think the motor he built was a piece of shit,.. and the mains and the rods where done is less than an hour...the talk got real heated... he said, I'm pulling that motor, and you're gonna eat your words,..so me and the owner went to breakfast.... when we got back...the motor was out... pan pulled... ever bearing in the motor was shot... it was one more getting on plane from windowing the block..whipped out the crank also..what had happened was ... they put a oil pan on that was powder coated on the in side... all that shit came off and got in the motor... pretty sure it was half done on the dyno...but I saved a lot of the motor putting it back on the trailer...LOL... I have a ton of these stories...so yes, I have a lot of respect for merc, just about every merc power has at least 100 more hp hiding in there, but they have found that spinning their motors to 5000 they last longer... and don't leak oil... the harmonics at 5000 rpms.. is way way less then 6500..I just took my 500hp out and ran it all day... not one drop of oil in the bilge...

 

[2FORCEFULL]

I always like to watch the "puff" on a compression test. the first bump of the needle. That tells a lot. Letting the the thing pump several times tells you less.. A little trick that helps save some time.

LOL... puff puff give..what I look for in a compression check is very little..I just wanna see that they are as close as can be to each other , and I look for low compression in joining cylinders...that says it probley sneezed a head gasket..low only one is probley a valve or rings... but you need to do a leak down at that point.... or just save your self some time and pull the heads..thats one of the things I hate about boat motor... you have to remove the manifolds just to run the valves... pain in the ass... what were they thinking..

 

[Holymoses]

I contacted merc racing today to ask about there motor exchange program. So they are now only offering that on there newer 1350,1550 Turbo Motors. Super informative told him what I had, let him know I have had zero issues and 475Hrs on twin 500efis. He said just freshen the stock heads new gaskets valve train and enjoy the boat for another 500hrs Sounds simple enough. Who can knock this out in Vegas/Henderson that's trust worthy and wont hold my shit hostage for weeks

 

[2FORCEFULL]

I contacted merc racing today to ask about there motor exchange program. So they are now only offering that on there newer 1350,1550 Turbo Motors. Super informative told him what I had, let him know I have had zero issues and 475Hrs on twin 500efis. He said just freshen the stock heads new gaskets valve train and enjoy the boat for another 500hrs Sounds simple enough. Who can knock this out in Vegas/Henderson that's trust worthy and wont hold my shit hostage for weeks

bob at marine center did my last one..