Mercruiser 7.4 bravo sprinkler

[Pete104]

That's it, keep it cheap!!!

 

[tpenfield]

I started working on my 7.4 while the engine was still in the boat . . . quickly realized that it was nearly impossible to do what needed to be done unless I pulled the engine, since they tend to take up a lot of space in the engine bay.

You might want to go ahead and do that now so that you can get good access to everything.

Got any pictures to post?

 

[sirhc76]

So I took a week off from the boat and was out of town for a week of work. Back to it now and actually got one more bolt off the exhaust manifold. The back three are very hard to reach and not coming out, even thought I could torch them but realized it wasn't going to happen. I think I have access to a lift that can get this out without dragging it to the ranch and using the bucket on the tractor. Looks like the engine is coming out, few questions before I goof up a few questions.

In reading my Mercruiser shop manual it looks like the lower unit may need to come off to pull the motor depending on the drive shaft? Are there special tools that I'll need to reinstall this and the engine after I pull it? Also read that I shouldn't remove the engine mounts, is this from the motor or the bolt between the mount and pedestal?

The engine was out just before I bought the boat, cant believe the PO didn't address this crap. It looks like they removed the two bolts that hold the mount pedestal on, is this the proper procedure? The single nut has obviously never been removed and should be replaced, its rusted out as well.

Pictures of the boat in general or pictures of the engine compartment?

Thanks in advance.

 

[tpenfield]

Engine removal is pretty straight forward.

Socket wrench set, screw driver set

Take the outdrive off ( 8 - 5/8" bolts)

Hook your chain/lift up to the engine lift points on the front and rear of the intake manifold
Disconnect the large connector harness leading to the engine
Loosen the exhaust tubes
Disconnect the throttle and shift linkages
Disconnect the power lead to the starter
Disconnect the trim sender and trim limit connections at the rear of the engine
Disconnect the ground lead at the flywheel housing
Disconnect the front and rear engine mounts
Disconnect the fuel line.
Disconnect the water inlet hose leading to the sea water pump
The engine is yours, lift away

Going back on you will need the alignment tool in addition to the tools used in the removal.

 

[sirhc76]

No Title

Resurrecting this thread. So what we see as Fall and Winter in Texas are usually busy for me so I just got back to the boat, well the wife forced me to. I managed to get the engine pulled, thankfully a friend had a friend with a service truck. I torched the last two head bolts off the 1-7 side of the motor and this is what we found. Manged to get the rusted exhaust manifold off the other side along with the two rusted head bolts. The lovely connecting rod pic is from #3 which is where the gasket went.

Now a few questions, block casting is 10237297, the heads are 10114156 and the crank is 10114188. The serial # on the engine tag is K193466, there are 6 bolts on the timing chain cover. Every thing I read leads me to believe this is a GenVI engine being that it has MK VI stamped under the timing chain cover and I do have roller lifters.

Should I go ahead and get the 100cc heads vs the 118cc that I have now and does it matter. Can I use an aftermarket intake and how about an aftermarket cam. I have a friend who has built racing engines for years helping me so hes obviously pushing for more HP

 

[Bondo]

I have a friend who has built racing engines for years helping me so hes obviously pushing for more HP

Ayuh,.... Welcome Aboard,..... So yer goin' for a full on Rebuild,..??

Is yer friend connected with yer local machine shop,..??
If not, go find the machine shop ya wanta work with, 'n tell the Boss yer wantin' a Boat/ Truck motor,....
Big Torque down low, 'n a redline of 5 Grand,....

 

[sirhc76]

Ayuh,.... Welcome Aboard,..... So yer goin' for a full on Rebuild,..??

Is yer friend connected with yer local machine shop,..??
If not, go find the machine shop ya wanta work with, 'n tell the Boss yer wantin' a Boat/ Truck motor,....
Big Torque down low, 'n a redline of 5 Grand,....

Yes full rebuild. The crank wasnt damaged and the bearings looked OK as well. I'm replacing all pistons and rods. The cam and lifters look OK as well. My local shop might be a little more than I need but yes I do plan to visit them for my head work. I'm still concerned about some of the parts. Looks like the head gaskets I bought last year might not be correct. The cutouts all match but they have two tabs with half inch or so holes up by the intake.

My local shop is Texas Speed and Performance, I know I cant afford a rebuild from them at this point so I'm trying to do most of the work myself. What I'm running into is a lack of understanding on what parts can only be Mercruiser and which can be Chevy. Friend with the know how leans to just getting Chevy parts but I don't want to mess anything up. Mercruiser Harmonic balancer, is extremely expensive while the Chevy version is what Id consider in line. Mine is rusted up so I'm going to replace it.

Thanks,

 

[Bondo]

The crank wasnt damaged and the bearings looked OK as well. I'm replacing all pistons and rods. The cam and lifters look OK as well. My local shop might be a little more than I need but yes I do plan to visit them for my head work.

Ayuh,.... No disrespect, but what yer lookin' to do is very Advanced Diy,....

For a long lived reliable motor, you really, Really oughta be talkin' to a machine shop, or buyin' a reman crate long block replacement motor,....

All of the motor parts are GM,...
Only the bolt on marine accessories beyond the long block are Mercruiser,....

No way I'd buy new pistons, 'n rods without proper block prep at a machine shop 1st,...
To Me, new pistons means new bores,... .030 over anyways,...