1972 or 76? mercury 1150 rebuild

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

well i learned the hard way this time that trying to skip certain things during a rebuild wont cut it..after seeing the spark plug in the condition it was i decided to find out why it did that and i did after taking the powerhead off the gasket had a blow by and let water in but funny thing is it only happened on number 4 not any other piston...piston number 3 slightly looks like 4 but not as bad(see pics) o lets see whats else did i find o when i took the crankcase cover off and was looking at the reeds i seen something that was not suppose to be in there it was the plastic piece that goes in the carb opening over the tube....still trying to figure out how it got there i do know that the piston is shot so new piston for that one the cylinder looks okay and i might be able to get away with honeing it..i let you guys decide. pics are below ill explain which piston is which and same as cylinder

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

cylinder number 1 cylinder number 2 cylinder number 3

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

cylinder number 4 the stuff at the bottom came out View attachment 187817 cylinder number 5 View attachment 187818cylinder number 6 View attachment 187819 piston 1 View attachment 187820 piston 2 View attachment 187821

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

piston 3 piston 4 piston 5 piston 6


forgot to mention the reason behind tearing it down. first thing this morning i did a compression check and 1,2,3,5 and 6 where all 145ish while 4 was 75psi if that

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

need some help guys im looking for new pistons and i did find them on crowleymarine for 121.09 but not sure of the size since they dont put that on there. i was looking on here but no luck at finding the ones that replace the 774-9137A12 its like they skipped it or something..according to my manual this is what i get

model 1150.... cylinder L6.... year 1974-78.... skirt 2.872.... above rings 2.863.... cylinder hone finish 2.875... 0.015 oversize hone 2.890

any help would be appriciated since this will be my first time doin something like this..thanks

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

anybody?

 

[carholme]

Re: 1972 or 76? mercury 1150 rebuild

Have to slow down, you are all over the place. In post # 16, you say that you had the powerhead rebuilt but don't say anything about what that entailed. What did you find damaged and how did you repair it?

In post # 25, you say that you are looking for new pistons. Why and how many? The Crowley manual shows the standard pistons as well as .015" over pistons but nowhere do you indicate that the cylinders were measured to indicate if you require oversize or not. What is the present damage to the pistons, rings and cylinder walls?

Are you using a manual and if so, which one is it?

Gerry

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

i didnt do a complete rebuild since my compression was over 140 on all cylinders at the time and figured if it aint broke dont try and fix it and leave it alone. so instead i decided to replace all the gaskets that i could replace. only damage that was done in the process was the 2 broken bolts i managed to snap off but was able to get them out after some soaking and elbow grease. i am looking for new pistons and rings if they dont come with new pistons cause after i got the timing corrected and took the boat down to the lake i had a blow out on a gasket that let water get into cylinder number 4 and damaged the top of the piston. no i didnt measure the cylinder walls to find out if it needs to be bored or not and just looking at the walls after cleaning them up there is no signs of major scratching or gouges and should be able to get away with just honing it. i will be taking the block to a marine shop to have it looked at and measured. while taking apart the block i noticed that there was a bolt with a wire strap on it from the factory which indicates that the powerhead has never been taken apart before. the rings on all the cylinders are in good condition and look like the where still brand new. i did break one while taking the crank out. i feel like im forgeting to mention something but dont remember... the manual i have is a digital download and i believe the factory one..it never said...sry if i all over its how i am with projects stupid A.D.D or A.D.H.D whichever is the one that makes you not be able to sit still or focus on one thing at a time

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

well its been a while since ive done anything with this thread but the latest update is that i took the block and some other parts in and had them blasted using plastic bead... took about 2 maybe 3 hrs to do it all and the outcome was good. i still dunno if i wanna paint the block or just leave it, kinda like the look of it.. since i cant upload pics of my phone ill have to do it off the laptop

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

 

[emckelvy]

Re: 1972 or 76? mercury 1150 rebuild

You'll need to put some kind of coating on the raw aluminum or it'll corrode.

You might consider something like this cast-aluminum-appearance low-gloss paint:

http://www.summitracing.com/parts/vht-sp995/overview/

VHT Nu-Cast Engine Coating - JEGS

HTH.........ed

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

i might have to look into that since its meant to keep the orginal look of cast iron or aluminum parts. thanks for that didnt think that it would corrode...even though its in freshwater it will still do that intersting to know. in the pics i have the covers on just to keep little furries out like mice and birds. the holes for the carbs are cover although it doesnt show it. it might be a while before i can do anything with the powerhead since i have to get my extra cash back up and take the block into a shop to have two bolts that broke off removed.. i figured since i dont have the right tools to compress the rings ill take everything to the local repair shop to have the pistons installed and put back into the cylinders. also since the engine is down for a while i might just go ahead and pull the cap on the boat and rip out all the water logged foam and check my stringers and transom and replace the flooring.

 

[mercurymang]

Re: 1972 or 76? mercury 1150 rebuild

Fresh water lakes have salt in them. BTW, i hear that clean, shiny engines run better than dirty ones

 

[mr 88]

Re: 1972 or 76? mercury 1150 rebuild

Huh ?

Fresh water lakes have salt in them.

 

[mercurymang]

Re: 1972 or 76? mercury 1150 rebuild

Yep. Though not at the levels of the ocean, all fresh water lakes have measurable salt levels to one degree or another.

 

[emckelvy]

Re: 1972 or 76? mercury 1150 rebuild

Fresh aluminum can oxidize over time, just from air exposure. If you're really craving a 'natural' finish, you could always give it a clear-coat.

SprayMax sells a 2-part clear-coat in a spray can, once you activate it you've got about 48 hours to paint before the stuff becomes unworkable.

Gives you a very durable, professional-grade finish and one can should be plenty for a powerhead.

You do have to wear a proper respirator, not a dust mask for this stuff 'cause it puts off some very nasty vapors which are health-hazardous.

SprayMax 2K Urethane Aerosol Clear Coat

Spray Max 2k High Gloss Clearcoat aerosol

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

ill keep that in mind emckelvy...but i think anything they make these days are hazardous to our health..heck look at any product and it usually says can cause cancer or something along that line in the state of california...not being mean to anyone on here that lives there just stating truth. but yes i do want to keep the original look of the powerhead and not paint it back to black. as of right now im waiting on warmer weather to come back and then i might start taking parts off to take the cap to my boat off and start on repairing the floor..hoping its not to bad the stringers seems solid just by tapping on them but looks can be deceiving. i did some looking at the transom area and it sorta looks like in the past the cap has been off before, ill know more when i get to that point.

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

okay started the process of removing stuff from boat to remove the cap but at a stand still cause the cap wont come off in front area is the cap fiberglassed to the floor and do i have to cut the fiberglass to release it or will it come up with the cap

 

[Vision91]

Re: 1972 or 76? mercury 1150 rebuild

quick update for everyone i just recently had the two bolts removed from a friend that rebuilds older mercs and did a good job at it, he didnt have to oversize drill it and retap it. Also he measured the cylinder walls and reported that they are still within spec and just did a hone on all cylinders so i dont have to bore and goto OS pistons. My ? is are the orginal pistons high dome or low dome ones, since i havent seen both of them at the same time i dunno which ones mine are. As of right now i have the prices on both pistons high/low ones and also ive been considering upgrading the rods to the newer ones. Are there any drawbacks to using those. I still need to take everything off the crankshaft and check the bearings for signs of wear, and also do some measurements on the crank as the manual states to make sure its still good since those are very pricey to replace. O everything has been sprayed down to prevent rust or corrosion.