mercruiser 7.4L engine replacement project

[mr300z87]

As I posted a few weeks ago see thread below,

http://forums.iboats.com/mercruiser...-7-4l-intake-manifold-620145.html#post4321024

I am working on a 1990 Sea Ray Sundancer 250DA that was a victim of Super Storm Sandy which includes a 7.4L engine replacement, and thought I would document it here. I have purchased what I believe to be the later 1996 7.4L which is complete minus the Weber carb and the power steering pump.
New Engine Last week I decided to start tearing into the old Engine (which was partially under water) to see what was salvageable. I think original engine had been replaced (boat is a 90) and this one is also 95-97 vintage engine but still had thunderbolt IV ignition and the Rochester carb. Once out I can see if there is a serial #. Not sure why it is white, some parts still had back paint on them??

This is what I found its not pretty when sea water meets engine.
Water in the intake ports not good!! engine frozen solid and the bottom of distributor housing broke off during removal as it is corroded in to the block. Next I started looking at the carb since I need one for the new engine, when I opened up I found mashed potatoes. I guess this is a combination of sea water/gasoline/aluminum corosion.

This lead me to a question, It look like the sea water pump/fuel pump assembly is good but when I drained the small amount gear lube from the pump housing where the fuel pump attaches it seemed diluted by fuel and had the smell of fuel. Should this be?? or is the fuel pump no good? I am looking to try and sell any parts that are salvageable to help with the cost of this project, but I do not want to intentionally sell a part that is bad.

Next on the list is to get this gross old engine block out of the boat, Then once I get a carb the plan to run the new engine on the ground to test. This is a long term project as money is always tight and marine parts are not cheap. I am sure I will have questions along the way and the knowledge on the site is just the place to look for answers. BTW this is only the 2nd GM V8 engine I have ever owned (the first is in my running boat) and I am much more comfortable working on BB and SM Mopars engines. (I wanted to name her "Wish it was A Hemi") wife says NO!!!!!!!!!!!! . I look forward to hearing your comments and advise.

I will try and figure out how to post pics not as thumb nails to make it easier to follow along.


Have a great evening

Mike

 

[Bt Doctur]

Re: mercruiser 7.4L engine replacement project

Not trying to bust your bubble but every bit of wiring, steering, electrical components will need to be replaced.Have you removed the drive and emptied the gas tank?

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

No bubbles busted. I understand (not so sure about the wife, its her boat) that each system on the boat will need to be gone through and as I stated this is a long term project and I do not intend on getting rid of my working boat until this one is in the water. My plan is to start with the engine and get it to a point where I have it running in the driveway, then move on to each system as I go.

The boat was on block in in one of the worst hit areas of the New Jersey Shore at a house with a lagoon in the back, when the bay waters came up the boat was lifted off the blocks and left leaning to starboard side up against the house. The water came in through the bilge drain plug which had been left out. I can see what looks like a water line on both the outside of the boat and in the bilge and I do not think the engine was completely submerged. Most of the engine and boat wiring harnesses were not under water and looked to be in good usable condition although I will be using the replacement engines harness with the Tbolt V ignition. There was no water inside the boat or up near the fuel tank so I am hoping to find clean fuel in the tank, but I wont know until I can borrow my friends fuel pump, I did smell OK though. Actually the fuel tank is one of my biggest concerns and could be a deal breaker!!! The good thing is the fuel filler and vent are on the port side so I am keeping my fingers crossed there some Gallons of good fuel in there. Steering cable is shot and will be replaced, but I am far from that. The Bravo 1 drive has been removed and I believe it is the reason the boat had not been registered since 2010, because it looks like a bearing in the prop shaft has failed. I am a little concerned about the gimble and transom housings as the gimble bearing is frozen and I hope it comes out. Both the Merc trim pump and the Bennet tab pump do not look to have been submerged either so again keeping my fingers crossed. Tonight I am hoping my neighbor can come over with his back hoe to lift out whats left of the engine, if so will post some more pics.

Mike

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Engine is out next step is to start major clean up of the bilge. Pics to follow when time allows.

 

[TJS]

Re: mercruiser 7.4L engine replacement project

Sounds like a fun project. You also might want to take the oil pan off of that replacement engine, pop a rod and main cap off and inspect the bearings. As long as you have a book it is not much different than a mopar. Also might want to replace the oil pump and screen while you are at it. Cheap insurance. Also a run in stand is a good idea. I built one years ago. See pics. I ran many engines on that. BBC and SBC’s. I since sold it. I am going to build another one though that does not take up a lot of room when not in use. It will be bolt together. I will also be able to adapt it to other engine families as well. Good luck with your project.

 

[HT32BSX115]

Re: mercruiser 7.4L engine replacement project

This lead me to a question, It look like the sea water pump/fuel pump assembly is good but when I drained the small amount gear lube from the pump housing where the fuel pump attaches it seemed diluted by fuel and had the smell of fuel. Should this be?? or is the fuel pump no good? I am looking to try and sell any parts that are salvageable to help with the cost of this project, but I do not want to intentionally sell a part that is bad.


Have a great evening

Mike

Howdy,

The sea water pump assy is probably "ok".

The fuel pump needs to be replaced. It's leaking fuel into the pump (gear) lubricant.

The pump is an AIRTEX 60932 which can be purchased from just about anywhere (including Amazon!) for about $50

(Airtex IS the OEM manufacturer for this marine pump.....If you buy the Mercury pump, it's an Airtex pump painted black!)) Fuel Pumps > Fuel Delivery System > Electric Fuel Pump

Most autoparts stores can order this pump out of their AIRTEX, Carter etc catalogs.

If that pump assy was run for many hours and the oil was completely diluted with gasoline, the bearings might be damaged or shot but they're replaceable.

Cheers,


Rick

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

TJ Thanks for the advice, I have every intention of running the new engine on the ground although not sure how or when yet. I would love to build a run stand like you pictured but I am not that good of a metal worker. I will proably pull the pan and have a look but have some time for that.

Rick I am looking to sell the pump and wanted to make sure I knew what I had. These pumps are big $$s so even if it needs a rebuild its got to be worth something. I figured the fuel pump was NG and was leaking, it says Carter on it. This boat has not been it the water since 2010 (well that is the last reg sticker) so who knows.

Going to keep plugging away at, and hopefully some day this will be my summer home at the Jersey Shore.

Mike

 

[HT32BSX115]

Re: mercruiser 7.4L engine replacement project

Rick I am looking to sell the pump and wanted to make sure I knew what I had. These pumps are big $$s so even if it needs a rebuild its got to be worth something. I figured the fuel pump was NG and was leaking, it says Carter on it. This boat has not been it the water since 2010 (well that is the last reg sticker) so who knows.

Going to keep plugging away at, and hopefully some day this will be my summer home at the Jersey Shore.

Mike

Yup. You can sure sell it. I sold a LOT of "stuff" on EBAY and it works well. Have a Look there and watch a few and you'll see what they'll go for.

No selling here though..... Against the rules


Cheers,


Rick

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

I plan on trying to unload as much as a can, looks like I have a buyer for the old frozen engine. I know no selling here. As soon as I can figure out how to post pictures not as thumb nails I will do so. I know there was a thread with instructions can anyone point me to it.

Mike

 

[HT32BSX115]

Re: mercruiser 7.4L engine replacement project

I plan on trying to unload as much as a can, looks like I have a buyer for the old frozen engine. I know no selling here. As soon as I can figure out how to post pictures not as thumb nails I will do so. I know there was a thread with instructions can anyone point me to it.

Mike

Since you're just starting out posting pictures you might consider using a free photo hosting site such as Photobucket or others,

Photo and image hosting, free photo galleries, photo editing

Welcome to Flickr - Photo Sharing

Picasa

Postimage.org - free image hosting / image upload

I use Photobucket, and all the others are similar.

Using a hosting site allows you to post, email or send the link to the picture instead of having to upload the entire actual picture or even video file every time you want to post it someplace like forums, craigslist, emails etc...

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

I managed to pull the engine out earlier this week but that was about it.

Yesterday was a big day because I dropped my daughter off for her 1st year at college :grumpy::embarassed:. Now if i could get out of my younger daughter's soccer tournament this weekend I might be able to go boating or at least work on one.

New used Weber carb arrived on thursday and looks great. Anyone know where the best place to get starter bolts? Merc wants $9 each for them :embarassed:, once I get those I should have everything I need to start the new engine. Another question. when I got the new engine I drained the oil to see it and put what ever 10w40 oil I had laying around in it just so it wasn't dry. Can I test run on the ground with the automotive oil? I once in the boat and ready for use I will put in the proper Merc recommended weight oil.

Trying to figure out this photobucket image posting so hope this works if so more pics to follow later today. Here is a photo of the old engine sitting on the ground, hard to believe that little engine can push that big boat.

have a great weekend.

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Its has been a busy week, and I have not really had a chance to work on my project let alone post pics. Last Sunday I took my friend and his boys out for a little fishing and tubing on my other boat.





We had a great day on the Shrewsbury River and Sandy Hook Bay even though the kids got a little sea sick while in the bay, they did manage some tubing in the river. The day however ended with a oil leak from the low oil pressure sender and a mess in the bilge. Its replacement was generously donated by the Sea Ray.

As mentioned above the engine is out thanks to my neighbor's back hoe, and even better the same neighbor put the frozen engine into a friend of a friend's pick up truck (SOLD). Last week my replacement weber carb arrived and it looks great. Now the last thing I need are some starter bolts and I am ready to test fire the new engine. Can any one tell me what wires need to connect to what for this to happen? The new engine is complete with engine harness and Tbolt 5 ignition which includes a knock sensor. Also can it run just sitting on the motor mounts on a pallet or does it need to be bolt down? I do not want 454 rolling all over my garage.
flying engine

new carb



If time permits (it is still boating season in NJ you know) i will start to strip and clean the bilge. I did manage to break on of the auto pump switches but all in all its not to bad in there. Also going to try and test the merc trim pump and the trim tabs pump.



I will post some after pic when all cleaned up.

All have a great day

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Not much to report but I do have some questions that I hope someone here can give me answers to. I am collecting all the gaskets needed to get the new engine running. The old engine had this thermostat housing with hoses going to the elbow (hoses 22 and 23) and 3 inch risers. It had full flow gaskets between both manifold/riser and riser/elbow.




The new engine had this style of thermostat housing


No hoses going to the elbows, so which gaskets go between the manifold/riser and between the riser/elbow? Restricted or free flow.

Second question how do I test run the engine on the ground? 12v to plus side of coil, to the starter and stater solenoid? Ignition module? Tbolt V.

As always any help is greatly appreciated.


enjoy the rest of the holiday weekend.

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Any body have some answers to my questions?? ^^^^^^^

As of today I am still waiting on exhaust manifold/riser gaskets, starter bolts and other miscellaneous part to arrive, which are all need to finish dressing the new engine. In the mean time I have built a engine console from some old gauges and scape wood I had laying around.



This weekend I plan to build an engine dolly so I can easily move the new engine for preparation to test fire. My friend was able me score me some really nice heavy duty casters for the dolly and aviation grade wire terminal to complete the harness to the console. If all goes well next weekend I will fire the engine and run for a little while to check oil leaks and other issues. Then I will fog and drain motor and put it in winter storage. While the weather is still and good and time permits I will start working on the boat.

Lucked out today and pick up a set of trim rams for cheap including the braided hoses, as one of the originals need a reseal which probably cost what I paid. I am in need of the choke rod for a weber carb with mechanical choke and I think I have found one but I am trying to confirm the shipment. I have dealt with this local company in the past with good results so I am hopeful it works out.

I knew this was going to be long project but with start of my daughters travel soccer season this weekend every Sunday from now until mid November has a soccer game and I have even less time to work on this project. Plus tomorrow we plan to take the Invader out (see signature file) as it is supposed to be beautiful. Priorities!!!!!!

Looking forward to waking the neighbors with the noise of an open exhaust 454 in the near future and if I can figure out how I will post a video. The only thing better would be the sound of a open exhaust BB Mopar .


All have a great weekend. As always all comments are appreciated.

 

[RollinEarly99]

Re: mercruiser 7.4L engine replacement project

opcorn: Subscribed

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Another weekend gone by and a little bit of progress, Friday my friend Al and I lifted the massive 454 onto a dolly I made out of a pallet and some free heavy duty casters (thanks Al and Don). Here it is sitting happily on the dolly it is nice to be able to move it around to work on.
Then Saturday Don and I installed the starter and connected my engine run console, we were able to turn the engine over with the starter switch. So before I went any further it was decided to do a compression test just to get a baseline. This motor has been sitting for an unknown period of time was cold. Here are my results. Sorry for the bad drawing art is not my thing.
I think the numbers are all good although would have liked to have seen them a little closer together, at least no dead cylinders.

No progress Sunday I needed a break so I went fishing with Don^ on his boat, it was a beautiful day on the water in NJ, but no keepers.

Next weekend I hope to install the carb and exhaust, strap her down and try and make some big block engine noise. If all goes as planned once it has run to operating temp I will do another compression test.

Still looking for some info regarding the thermostat housing see post above? Any thoughts on compression numbers?

Have a great week

Mike

 

[Speakrdude]

Re: mercruiser 7.4L engine replacement project

Are those "BATS" hanging from the rafters?

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

No bats, usually this make shift garage houses my 68 Plymouth Satellite and I do not work in it. The car pretty much fills it up. A bunch of years ago my area had a REALLY bad gypsy moth infestation. They were so bad that the trees had no leaves left by then end of July. So what yours see are the cocoons form the gypsy moths mixed with cob webs that my lazy butt never cleaned up :facepalm:. The Plymouth doesn't care that they are there.

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Not much to update of late life has been keeping me busy. Last weekend I continued to prepare the engine for a test run, but to be honest I have been procrastinating because I am scared:mad-new:. Maybe today is the day.

I have started to pump fuel out of the boat and I happy to report that I found a full tank of usable fuel, (tank is 99 gallons). I did come across a possible set back though



This crack is in the hull between the Motor mount and the Keel, I have posted this thread

http://forums.iboats.com/boat-restoration-building-hull-repair/sea-ray-250-sundancer-hull-damage-need-advise-629517.html

At this point I am going to keep plugging away and if I have to do some fiberglass repair so be it.

Have a great finish to the weekend

Mike

 

[mr300z87]

Re: mercruiser 7.4L engine replacement project

Today was a great day I successfully ran the engine. I started off just squirting a little gas in the carb to see if it would fire, and it did. Next up was to connect some water to the raw water pump, reinstall the raw water pump belt and connect a fuel source to the carb. After a few crank and some more gas down the carb, it fired up and ran smooth. Hope the video link works. Big Blocks with open pipes sound sweet.:joyous:

Could not figure out how to upload link to Youtube so I just posted the link

https://youtu.be/tLG1asOao2U

Next weekend a quick run to operating temp, take a base line compression test, then winterize so I can put it away until spring when I will install in the boat.

have a great week

Mike