89 Mercruiser 5.7 questions

[BWeiss85]

Hi all, I'm looking for a little help/advise regarding the 5.7 merc I have in the boat I just picked up. It's in an 89 Sea Ray 190BR if that helps.

My first question regards the carb and starting. On land and hooked up to the muffs, she starts and idles just fine. Upon launching, if I stop the truck short a tad, so the water inlet is barely submerged, she start with a tad more fuss, but not a ton. However, if I back her all the way in the water, it takes quite a bit to get her fired. Sometimes I need to open the engine cover and operate the throttle a bit while my GF turns the key to get her to finally go. Any idea what this is? Am I looking at a carb rebuild?

Second, eventually I would like to go to EFI to avoid the situation above altogether. I have done as much research as I can, but always wind up with incomplete or conflicting info. Will Vortec or LS heads fit on to this 5.7 block? I have found a few deals on complete motors with the ECU out of late 90's trucks or suburbans, and would like to swap the heads, intake, TB and ecu over. Is this possible or am I dreaming?

Thank you in advance for any input and/or advise!

 

[Bondo]

or am I dreaming?

Ayuh,..... Welcome Aboard,...... Yes,.... Efi ain't worth the money, if done Right, aka: Marine rated,....

Is this carb a 2bbl. or 4bbl. carb,..??

Have ya inspected the contents of the fuel filter for Anything but clean fresh gasoline,..??

What's the history on the motor,..?? When was it last "Tuned Up",..??

 

[alldodge]

Hi all, I'm looking for a little help/advise regarding the 5.7 merc I have in the boat I just picked up. It's in an 89 Sea Ray 190BR if that helps.

My first question regards the carb and starting. On land and hooked up to the muffs, she starts and idles just fine. Upon launching, if I stop the truck short a tad, so the water inlet is barely submerged, she start with a tad more fuss, but not a ton. However, if I back her all the way in the water, it takes quite a bit to get her fired. Sometimes I need to open the engine cover and operate the throttle a bit while my GF turns the key to get her to finally go. Any idea what this is? Am I looking at a carb rebuild?

Howdy

I would look at the carb, and the reason why is I think your float is set incorrectly. When your on a hose, I would guess your on close to level ground. When your launching, the boat is tipped more so you might be getting to much fuel.

Second, eventually I would like to go to EFI to avoid the situation above altogether. I have done as much research as I can, but always wind up with incomplete or conflicting info. Will Vortec or LS heads fit on to this 5.7 block? I have found a few deals on complete motors with the ECU out of late 90's trucks or suburbans, and would like to swap the heads, intake, TB and ecu over. Is this possible or am I dreaming?

Thank you in advance for any input and/or advise!

You can go EFI and use TBI but you cannot go with items from a truck or car. Marine equipment is designed to keep things from blowing up in an enclosed area. A truck or car is open and allows air to move around it. A boat is a enclosed system and gas vapors can build up. If you get your carb set up correctly you won't have issues

 

[BWeiss85]

It's a 4 barrel, don't know the brand off the top of my head, could be factory.

Dunno much about the motor, other than its an 89 5.7l Mercruiser. Should I go ahead and pick up a carb rebuild kit? Or do you think tinkering around a bit and setting the floats will do? I guess I can start with that, then work my way up to a carb kit if needed.

 

[alldodge]

Not having a serial number I'm going to figure this would be your motor
http://www.mercruiserparts.com/5-7l-gm-350-v-8-1988-1995-0b525982-thr

It could have a Rochester or Weber carb. Need to find out if fuel is dripping from the carb before taking it apart. I'm guessing this is the issue from what your saying but need to verify. Get it running on the hose, then stop the motor. Go back and see if fuel is dripping, if not, find a way to get the tongue higher and see if that has an effect and causes it to leak.

So far as what carb, post one more time, take a pic of the carb and post. Also look for a number stamped on the side of it, or a tag

 

[Alumarine]

Sometimes I need to open the engine cover and operate the throttle a bit while my GF turns the key to get her to finally go. Any idea what this is? Am I looking at a carb rebuild?

You can operate the throttle with the control handle.
There should be a neutral only button so you can operate the throttle independently.

Have you tried starting it by using the throttle only button, pumping the throttle fully a couple of times and then leaving the throttle cracked an 1/8 or so?

 

[Rick Stephens]

My first question regards the carb and starting. On land and hooked up to the muffs, she starts and idles just fine. Upon launching, if I stop the truck short a tad, so the water inlet is barely submerged, she start with a tad more fuss, but not a ton.

You can find the complete service manual at http://boatinfo.no In the manual will be a section on rebuilding the carb and setting the float level.

One thing metioned was using the throttle only button to operate the throttle without the control handle putting the boat into gear. I have an '89 that the control handle itself is wriggled or worked outward - toward the driver - to disconnect the shift cable and allow just throttle to be opened. That can help a a lot getting things running.

Another thing of note - Do not start your engine with just the water inlet submerged! The water pump in the outdrive is designed to be under water for it to prime and it is several inches above the inlet. If the pump itself is not under water, and the motor is started, the impeller will burn up as it is lubricated and cooled by water. Lots of people who have tried running a Mercruiser sterndrive in a barrel of water that only covers the intakes but doesn't come all the way up to the cavitation plate have burned up impellers. Your problems are not related to how far you back in.

 

[BWeiss85]

One thing metioned was using the throttle only button to operate the throttle without the control handle putting the boat into gear. I have an '89 that the control handle itself is wriggled or worked outward - toward the driver - to disconnect the shift cable and allow just throttle to be opened. That can help a a lot getting things running.

I'll give that a try. Mine doesn't have a button, so I wasn't able to do that before. I'll try to wiggle my control out when I get home. That should greatly help things get going, since just opening the throttle directly on the carb a tad and she fired fairly easily. It seemed odd that there was no way to operate the throttle without being in gear, so hopefully you just saved me some frustration...

 

[Alumarine]

I'll give that a try. Mine doesn't have a button, so I wasn't able to do that before. I'll try to wiggle my control out when I get home. That should greatly help things get going, since just opening the throttle directly on the carb a tad and she fired fairly easily. It seemed odd that there was no way to operate the throttle without being in gear, so hopefully you just saved me some frustration...

As Rick says if you don't have a button there will be another way to activate neutral only.
That way it will set the choke as well when cold.
Make sure when cold that the choke does close almost all the way. Approximately .080" gap.

 

[Bt Doctur]

If you dont have a button to push in then you have a handel that pulls out for throttle only

 

[BWeiss85]

Thanks all. I'll definitely check that out when I get home. I used to boat around 3-4 days a week for work, but those were all pretty much new with 4 stroke efi outboards. This is the first I've dealt with a carbed boat, and an I/O, so I'm definitely on the learning curve.

Thanks again for all the help!

 

[BWeiss85]

Well, wouldn't you know it, but the control stick pulls out and allows throttle only operation. I plan to have the boat out this saturday, we'll see if that solves my problem.

You live, you learn, I guess.

 

[Rick Stephens]

What doesn't kill you makes you stronger.