mercruiser 7.4L engine replacement project

mr300z87

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Sep 15, 2010
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Here are a couple pic of today. It was a gorgeous day.
Getting her untied
2016-10-07 11.42.38_zpsadzagpns.jpg
In the water
2016-10-07 11.53.26_zpsuesmy6zz.jpg
I must say she looks much better in the water than in my driveway on the trailer.
 
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alldodge

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That's a good looking boat, and a boat like some other things look much better wet :rolleyes:
 

mr300z87

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This morning I went out and disassembled the helm and saw that I did not pay attention to what I was doing when I installed the new helm and put it in upside down. My guess is the helm is built for many applications and even thought it is keyed it can be put together wrong. So we flipped it over re-attached the cable (on top as opposed to the bottom) and bolted it back together. The boat will now steer correctly turn to port steer to port :), not to many bad words were said and there was no blood. I must say that it was a 2 man job, one in from the top to hold the wrench and the other under the dash with the ratchet. I suspect that when Sea Ray built this boat some 26+ years ago they had not intended for any one to do anything under the dash. I have been contemplating cutting some access panel in the cabin to facilitate work under the there in the future. Unfortunately our forecast is for rain on and off all day today and 15-20 MPH winds tomorrow, so no boating this weekend. Maybe next but I am running out of good NJ boating weather.
 

harleyman1975

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May 12, 2003
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Just pulled one of our boats out yesterday but still have one in for a little fishing if the weather permits. Glad that Matthew didn't visit you! I know you will get a water test in this year.
 

mr300z87

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As of now we are planning splash take 2 this coming Friday assuming the weather is like predicted.
 

mr300z87

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TODAY WAS A TOTAL SUCCESS We launched the boat in Barnegat Bay and went for about a 1 hour cruise, there was a strong breeze out of the north west and the bay had a mild chop. Once out of the no wake she I throttled up and she jumped right up on plane with no issues. We cruised at 3500 RPM 27 MPH, the 7.4L ran strong and smooth. Let me just say that this is a totally different boat with a 330HP 7.4 vs my friends with a 260HP 5.7L. Below are link to the videos my friend shot, he texted them to me so the quality is not so good, I try and get the originals from off his phone to re post. I wanted to thank my wife Michelle for pushing me through this build, my friend Don for helping put this thing together and Friend Jeff for giving her to us. There is still a lot to do before she goes in for summer fun in 2017 but this was a big step.
https://youtu.be/lQRzEOi4bGk
https://youtu.be/6OejqnKlX74
 

mr300z87

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Messages
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Yesterday I took to the day off from boat work to split some firewood to keep the wife warm this winter. Today I am going to go out and make a list of must fix and want to fix items in preparation for 2017.

One of the things I have been struggling with and is at the top of the MUST list is to figure out what cold start procedures works for this engine. My 5.7L with Rochester 4 barrel took (she is dead now) 1 pump of the throttle to add fuel and set choke and she would fire right up. The 7.4L Weber 4 barrel I even with 3 pumps will not fire off COLD without a squirt of gas into the carb. The carb was rebuilt before installing and adjusted per the MerCruiser manual. Once it starts she runs and warm starts no problem. Anybody out there with a 7.L Weber carb engine that can share their cold start procedures. The choke type is a divorced setup (not electric) and the bimetallic spring is new. I will be checking the choke settings at some point before I fire her up again which will probably be for final winterization.

I can not stop thinking about our sea trial the other day and how excited I am about getting her finished for next year.

Have a Great Day
 

alldodge

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Since new my 7.4 has been hard to start if it sits for a few days (same carb as yours). If it sits for a week or more it really takes some cranking. The bowl just dries out. I crank a bit, pump a bit, and repeat. Once it starts to hit, it will then fire up and go.
 

HT32BSX115

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Dec 8, 2005
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One of the things I have been struggling with and is at the top of the MUST list is to figure out what cold start procedures works for this engine. My 5.7L with Rochester 4 barrel took (she is dead now) 1 pump of the throttle to add fuel and set choke and she would fire right up. The 7.4L Weber 4 barrel I even with 3 pumps will not fire off COLD without a squirt of gas into the carb.

I didn't rebuild my OEM carb on my 97 7.4 when I installed in my 87 Four Winns. I did however disconnect the automatic choke......... Actually I just adjusted it FULL open and disconnected the power to the heating element) . Never did like those things!

Boating for me is always in the "Summer" or warm weather so it never really needs a "cold start" capability.

Now, having said that, I do give it a couple of splashes of fuel into the carb after sitting for the winter.

After that I only need to "pump" the throttle 2 or 3 times to get it to start in the morning and I have to do a little warm up after that. I have closed cooling so it warms up quickly and is fine for the rest of the day......for each subsequent start, I only pump it once and it fires right up, even after sitting for 2 or 3 hours....

If you cannot get it to start reliably after a few pumps of the throttle, you might check out the accelerator pump. maybe 3 "pumps" isn't giving you enough fuel. It should be MORE than enough to start it cold.

By the way, I don't remember if I suggested it before, but if you want even better all around performance, start looking for a Bravo III drive (1.81:1 or 2.00:1). Your 25ft boat would be a perfect fit with one of those and you'd love it. I originally looked fora Bravo I and came upon this III. I was a little leery of it until I ran it. I wouldn't trade it now. Mine came out of a 1998 24ft Bayliner cuddy

Cheers,

Rick
 

mr300z87

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I did some work on the boat today, mostly cleaning and going through the electrical and pluming systems to see what works and what needs to be fixed. I did not feel like dragging the hose out to the boat and running it so I did not mess with the cold start issue. I too boat in the summer time and the choke could probably be by passed, but with this bigger cabin boat we may keep it in the water longer and get some fall usage out of her so it would be best if the choke worked.

There are a few items that need to be address before spring launch, most importantly I have noticed that a couple of bow rail stanchions are loose and need to be tightened, however the worst 2 are buried behind storage shelves on the inside and for the life of me I can not seem to figure out how Sea Ray assembled this thing. I will figure it out and get the wife to come out and get her hands dirty helping. This is a safety thing and it is important that the boat is safe. Next on the priority list is replacing the main power cables from the battery to the switch with the new ones I have. Another Item high on the list is the bow mounted deck plate into the anchor locker, it is completely trashed from 26 years of UV beating on it. Also on the priority list is to get the trip tab pump installed and wired. I need to drag an extension cord out to the boat to see what happens when I plug in shore power (batter charger, refrigerator, and 110 outlets). I also have a Lowrance HDS5 GPS and transucer that I picked up used last spring that needs to be installed. The last must do is to replace the wood in the panel and pull out seat that goes along the back, the panel is completely rotten and when my friend sat in the seat it make some noises like is was not to healthy either. Here this photo shows the rear seat the panel that needs to be replace surrounds this seat all the way across the back. The part that is rotten the worst is on top behind the back rest cushion.
2016-10-07 15.56.18_zpsrgvtszne.jpg
I am sure I will find a few other item to add to this list.

Then there is the I would like to list which include fixing the 2 cabin lights that don't work, replace cockpit speaker grills, upgrade to modern stereo with bluetooth (it's got a cassette player :eek:), test/repair fresh water system, replace crusty looking plastic thru hull fittings (qty 9), install either a port-o-potty or maybe a permanent head with holding tank, purchase a new or used bimini and make a new plastic face for instrument panel.

These items should keep me plenty busy, now if work did not get in my way and funds were unlimited all would be done by the end of October. LOL

I would love to find a Bravo 3 but right now I need to use what I got and B3 drive and prop set would most likely use up my 2017 slip budget. If this boat were a small block like my friends a B3 would definitely be on the must have list. As I stated in my previous post the 7.4 L make this a totally different boat than my friends identical but 5.7L/Alpha powered Sundancer 250. Have a great night
 
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HT32BSX115

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I would love to find a Bravo 3 but right now I need to use what I got and B3 drive and prop set would most likely use up my 2017 slip budget. If this boat were a small block like my friends a B3 would definitely be on the must have list. As I stated in my previous post the 7.4 L make this a totally different boat than my friends identical but 5.7L/Alpha powered Sundancer 250. Have a great night
It's something to keep in mind! The performance difference is nothing short of spectacular in a big boat!
 

harleyman1975

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May 12, 2003
Messages
959
Awsome news! You might consider a new edelbrock carb if you can't get yours to stop leaking down. Most likely a stuck check ball in a hidden passage.
 

mr300z87

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Sep 15, 2010
Messages
694
After almost 4 years since my first post on the this thread I am about a week away from splashing her. I took the week off and spent most of it working on getting ready to splash yesterday. I did not make it unfortunately. Here a some of the item I got done even though most are not engine related this is all about re commision and super storm sandy victom back into service.
Fresh coat of AF bottom pain
2017-05-31 18.51.15_zpspavimhmv.jpg
2017-05-31 18.53.31_zpsvipkpkmu.jpg
Had to replace to o-rings on the B-1 drive top and shifter covers then pressure test and refill with gear oil. Hold steady after an hour
2017-06-01 12.56.37_zpszryue2gk.jpg
Installed VHF radio
2017-06-02 16.50.53_zpskcmoidfh.jpg
Installed GPS
2017-06-02 18.49.43_zpsh5xx2gw0.jpg
Today I fired her us got the engine up to temp and changed oil
2017-06-04 12.07.51_zpsjccpjkdu.jpg
Then I gave her a bath inside and out, She is looking pretty goods. I also pulled the shore power cord and plugged her in to house power. Battery charger was charging and all the AC outlets worked, but the refrigerator did not seem to come on, I did not try the stove.
I have a couple must do items left before launch next weekend. The 3 points on the bottom where the blocks were need to touch up with bottom paint. The outdrive also needs to have some touch up paint done.
Fingers crossed she will be at her new summer location next Saturday morning.
2017-05-28 09.47.25_zpspymhbeye.jpg

Tomorrow its back to the real world WORK!!!!! Have a great night
 
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