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1997 43 mercruiser alpha carb problems overheating no acceleration

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ycart0

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"This boat is a 1997 bryant wi

"This boat is a 1997 bryant with a 4.3 mercruiser. carburated, alpha


Today we took our boat out want to do some sight seeing in the fall being the 1st year owning a boat. Hoping to get to go out a few more times before storing it for the winter. All summer long this boat has had a starting problem. Hard cold starts. We normally take it out every other weekend. Can't figure the exact problem out but here's what I do to get it running. With help from another person. While they crank it and having the shifter in foward position, just a little throttle, I slowly pore gas in the carb, I'll some times manually mess with the choke. Which I think sees to help. Nomally between 5 and 30 minutes I have the boat running fine ready to go out. This is the first problem

Today when getting the boat ready. I did my normally routine. I noticed one thing different. I think I may have poured too much gas in because I had a back fire. Didn't pay it too much attention. Once it started seemed to miss alittle but clear up. So we headed for the water.( btw I use the host attachment for a water supply before going to the water). Once we get the boat in the water we head out. Running about 2000 rmp's for about 10 minute I start to increase the throttle. I realized that the more thottle i gave it that the rmps wouldn't increase and the boat wouldn't speed up. We had family in from up north, didn't want to upset them but I told my wife that we may have a problem. Wait and behold within another 5 minutes the warning beeper went off and the engine was up to close 180 to 200 f. I quickly turned off the engine. Then engine was hot and I don't think there was any water in any of the hoses when I was checking. A nice guy pulled us back to our trailer. Once there I trailered the boat and the temp was back down to 125. When I got home tonight I check the hoses and there was water in them. Not sure the best place to begin trouble shooting or what to try. I have the seloc stern drive manual and will be reading there also.
Other advice I need to know is storing this for the winter. I just checked the weather channel and they are predicting monday tue and wednesday to get below 32 degrees. I think 28 will be the coldest. If you want to check Our zip is 37323. will it be ok if I haven't winterized it yet or do I need to get bus? Not sure so what I have done was I removed some of the water plugs for about 30 minutes then put them back. A problem there is that I only found 4 and I was told there was five. I found 2 on each side of the engine. 2 on the block, 2 on the hose ends. Where would that 5th one be? I would like to get all these problems fixed before taking it back out on the water. or at least by next spring.

Sorry to be so lengthy just want to give as much info as possible. If you need more just let me know thanks be blessed Tracy"
 
"with a carb, you normally pum

"with a carb, you normally pump it 3-4 times before starting,the accel pump will squirt some gas down the carb.
the missing 5th might be on the large hose that goes from the therm housing to the circ pump,it`s a joint in the hose that has a drain plug"
 
"My 1996 4.3 LX only had 4 dra

"My 1996 4.3 LX only had 4 drains; two on the block and two on the bottom of the manifolds.
Check; you may have one as Bd describes, and you may also have one on the inlet water hose, low on the front port side, just where the water hose comes up to the stat housing.

Your overheating may have been caused by weeds or something blocking the water intakes, or a bad pump impeller. If the impeller is original, it is long overdue for replacement. That would be the first suspect.

If you are planning more boating before winterizing, you can get by for a few nights at those temps by putting a 100 watt lightbulb in the engine compartment low in the bilge. Then button it up as best you can to keep the chill out.

Is your choke closed all the way for a cold start? If not, the choke mechanism or heater housing needs adjusting.

Rod"
 
"The hard starting and no resp

"The hard starting and no response with throttle up is possibly 2 problems with the carb.
The throttle up problems sounds like a bad accelerator pump. Its a cheap rubber pump thingy that squirts fuel to the engine when throttle is advanced. All carb engines act the same way when accelerator pump fails.
The accelerator pump MAY be ok but the delivery system is plugged giving same result.
The hard starts could be very low fuel level in float bowl and or plugged jets etc.
The carb problem could cause engine to run hotter than normal by running lean from lack of fuel.
The other over heat problem could be plugged or damaged raw water pump.
Carb rebuild kits contain many parts. Most kits are somewhat universal in that they contain parts for several carb's and you only need a few of the parts and toss the rest when done. Most of the parts are not needed and typically gasgets, accelerator pump and float needle and seat are the only parts needed replacing. Other than that, a good cleaning is a MUST using compressed air to blow out the fuel and air passages. Never sick anything into the main jets that will cause the bores to be scrached.
DANGER
Pouring fuel down the cab can cause that fuel blow back out during back fire and cause fire or explosion!!!! If you must, use starter fluid in short bursts."
 
"Thanks to everyone who respon

"Thanks to everyone who responded. Wanted to update you all on my progress and see what you think. Today was my first real chance to tinker with my boat since Saturday. Hooked the water hose up to it. Same problem as usual. Took me about 30 minutes to get it running. The first thing I notice was that there wasn't any fuel in the carb that I could see any ways. So trying alittle different I pour about 4 oz of fuel in the back of the carb. Question on the fuel pump. Does it only pump when the ignition is turn over. Should I check the pressure on the fuel pump? Or is it safe to rule this out? I went off to the lake just to test it out. Once in the water I pushed the throttle all the way forward. The motor wanted to spitter and sputter and loss of power. This time slowly easing into the thottle it picked up fine. After about 6 times it finally started to smooth out. I am still leaning towards the accelerator pump, any other suggestions there? With the carb problem, is it possible to be corrected with cleaner or is the best thing to do is rebuild? How hard is it to rebuild. It's a mercruiser 4 bbl. This time no over heating but I didn't idle hardly any. My plan there is to change the water pump empeller? Some web sites say to take the drive completely off. The mechanic at the boat place said just take the bottom half off. Leave the rest on. Whats the best way, easiest, simplest way. Tonight is suppose to be the coldest this week. I think about 28 is the low. I have the light but in the bottom of the bilge. I went ahead and changed my oil but I am waiting on the drive oil untill i do that water pump. In the process of changing the oil the boat place gave me the wrong oil filter. I knew that this engine was a 1997 4.3 gm So I went to wal mart and bought a fram ph3980 in place of the one on it. It took about 5 seconds for oil pressure. (Is that normal?) And is this oil filter ok or should I change it for one like what came off it?
Tell me what you guy's think
For the fuel stabiilizer I am using Sea Foam Motor Treatment. ( 2 cans for approx 38 Gal of gas) For fogging the engine I used 1/2 can of seafoam Deep Creep.
Thanks to everyone
Be Blessed Tracy"
 
"When pouring fuel down the ca

"When pouring fuel down the carb, 4 oz is waaaaaaaay to much! You are probably flooding the engine. Best to use a shot of starting fluid or only a teaspoon of fuel.

Fuel Pump issue-
Is it elect or mechanical? Mechanical only pumps when engine is cranking or running. Remove supply line from carb and direct it into a quart jar. REMOVE COIL WIRE COMPLETLY to keep engine from starting or stray spark ignighting the fuel!!! With help from someone, Crank engine and observe fuel sqirting into jar. It should be steady and forceful squirts with no spruttering. Should deliver a cup of fuel in about 5 seconds.
Elect fuel pump runs all the time or at least when the line pressure is low. It should be steady flow with no spruting. Same amount of delivery as mechanical.
MAKE SURE YOU DONT SPILL ANY FUEL AND HAVE A FIRE EXTINGUISHER HANDY.

Your last run on the water sounds like a bad or plugged accelerator pump system. It is fairly easy to fix.

Oil Filter-
It takes a few seconds for a new filter to fill with oil and pressure to build up. From now on, the oil pressure will build up as soon as the engine starts.

Impeller-
A weak impeller will tend to over heat at idle but run somewhat normal at higher rpms. Your boat guy is correct, you only have to drop the lower unit."
 
"It takes a few seconds fo

"It takes a few seconds for a new filter to fill with oil and pressure to build up."

Always prime a new filter w/fresh oil before installation. Slowly fill it until nearly full.
 
"Tracy;
My opinion; In future

"Tracy;
My opinion; In future always use Merc or other high quality filter. Frams are rated by most on this site as sub-standard.

Same for oil. Don't use some cheap 5W-30 or 10W-30. Stick with Merc 25W-40 or another high quality brand of your choosing, but obvserve the 25W-40 rating.

My 1996 4.3LX was a bear to start after it had sat for a while also.
Here is how I solved it:
(I posted this on this site about a year ago. It is copied here)

"Unless the engine is running, the electric fuel pump does not run, even with the key in the “ON” position. This is because the pump circuit is equipped with a low oil pressure cutout switch that is intended to shut off the fuel pump and kill the engine in the event that oil pressure is lost. The pump is only energized when the key is in the “START” position, during which time the cutout switch is bypassed. The starting procedure can be long and difficult because the gas must then be pumped from the tank through the filter and lines, and fill the carb bowl, before the engine will fire. Meanwhile the voltage to the pump is around 8 volts, and the pump runs painfully slowly. It can take a full 30 seconds or so of starter engagement before the engine will start. This is hard on the starter and the battery.

The cure is to “prime” the carb bowl with fresh gas before attempting a start.
This is what I did to fix the problem with mine. I wired up an automotive/marine rated momentary contact pushbutton switch to run the electric fuel pump just before starting. I am pleased to say it works perfectly. When the switch is pushed, I can hear the fuel pump working for about 4-6 seconds, then it cuts out when the carb bowl is full. Then following my normal cold start procedure I give her one small throttle shot in neutral lockout, and hit the start key. Bingo, she starts right up on about the second or third firing stroke and runs perfectly.

The pushbutton switch is rated at 15 amps, and I installed it just beside my key switch. I took a +12 volt feed from the "I" terminal of the key switch. (This terminal is hot only with the key "ON". This means the pump cannot be activated without the key on.) Then I ran a single 14 gauge wire from the other terminal on the switch back to the engine and connected it to the existing purple/yellow wire running from the starter solenoid to the electric fuel pump. This effectively bypasses the oil pressure cutout switch and feeds +12 volts to the pump when the switch is pushed. Pretty simple job."

Another simpler way to do this would be to install a manual primer bulb (the kind used for outboards) in the fuel line between the fuel tank and the filter.

Hope this helps,
Rod"
 
"Tracy...

If electric fuel

"Tracy...

If electric fuel pump....pressure spec. is 6-9 psi.

You said "The first thing I notice was that there wasn't any fuel in the carb that I could see any ways." How could you see? Was this by moving the accel linkage and not seeing anything squirt down the carb? That would deffinately indicate the accel. pump, unless the fuel bowl is dry. That dry fuel bowl would put you back to the fuel pump. When was the last time that fuel/water separartor filter was changed? If you don't know the maintenance history of the boat, change it now. It will restrict fuel flow to the carb.

As Bill said, you're pouring way too much fuel down that carb, = fire hazard, flooding, but also raw liquid gas washing down the cyl. walls and taking away all the oil for the piston skirts on start up (wearing out the cyl.walls). Loading the oil pan with raw gas, dilluting the oil in the pan so it now has no lubricating properties.(killing your crank and cam bearings). Good thing you changed it. Fram filter,...hmmm., it'll work for this time, but after that get it off there and don't put another fram back on it - ever. Oil filter controversy on this forum about a year ago. If I can find the link to the filter study, I'll post it for you.

Overheating - a few good points already mentioned, such as impeller, lean fuel mixture means combustion chamber temps up, but don't forget thermostat and then water pump (less common, but just like your car)

Wrench"
 
"First of all I just want to s

"First of all I just want to say you guys are awesome. Alot of Info here for me to start with. + I have all winter long... Thanks

Rod on that push button switch that operates the fuel pump, how exactly does that work. Is that like an on off switch that you push once for on then again for off. Or is it a switch that you push and hold for approx five seconds. Or is this fuel pump designed to turn off once the carb is full. Just trying to get a better idea of how it works. I have the wiring schmatic and I see the Oil saftey switch you are talking about in the schematic.

Guys is there a way to clean plugged accelerator pump without completely taking the carb off the engine. How do you tell if it is just plugged or if it is bad? I have the surging and hesitation when in the water. Last time having the boat out after the 5th full thottle that went away. The time before that I never could break the wake. Then within minutes I over heated. Can you buy just the accelerator pump Or is it better to just get a rebuild kit and tear it apart? And again how hard is it to rebuild the carb? How can i tell if i have a rochester 4mv 4bbl carb or weber wfb 4bbl carb? I think i have the weber.

Wrench the carb at first is completely dry. Once i pour fuel in it it trys to start. Something that I have tryed basically because I'm still learning this carb is fill up the fuel bowl. When can you tell that the carb bowl is full of fuel. After reading rods message I think my main cold starting problem is that fuel pump delay. So is there a semi safe way to manually feed fuel to the carb untill the fuel pump gets the fuel up to it? Wrench, at the beginning of the season I put a new fuel water seperator on. But it took me for ever to get the fuel back up the to carb. But once we got it running it was fine.

Question on winterizing. I took out the 4 plugs, never found that 5th...(if it there is a 5th) let the water drain. Then put the plugs back in. Then I took off the big hose by the theremostate and poured 1 gallon of rv environment safe antifreeze in that hose then put the host back on. Is this ok. Is it neccesary. Or is there a better way.

As far as the drive unit what do I do to winter rize it. All I did was dropped it down to almost touching the ground. Is that good or is there other things I need to do.

Thanks for all the help. I'm sure Ill get more questions in this process of getting this thing up to par.

Be Blessed Tracy"
 
"Tracy;
Sounds like you drain

"Tracy;
Sounds like you drained the engine just fine.
The only other thing you maybe should do is break a hose clamp down on the water inlet hose low on the port side, either before or after the PS cooler. That will drain the entire inlet water hose. The place where it runs down by the PS cooler is a low spot and retains water.

The push button switch is a momentary contact type. So you just hold it down for a few seconds until the pump quits. You can easily hear the pump working when the engine is not running or cranking.
The pump shuts off when it reaches about 6 psi output pressure, which happens when the carb bowl is full.
As I said that push button completely eliminated hard starting on my 4.3.

The good thing is you won't leave the push button switch on while running, which means the oil pressure cutout switch will operate as originally designed. It will kill your engine in the event of loss of oil pressure.

Rod"
 
"Change the anti-drainback val

"Change the anti-drainback valve on the fuel tank. It's where the fuel outlet hose is connected. Have you changed the fuel pump filter?

The Weber 4 barrel carb is listed in the Merc. parts listing for 1996-1997. The carb numbers are stamped on the front or side of the bowl. There should be a green or gold alum. number tag on the top of the bowl under one screw. That tag IDs the correct carb when getting parts of a new carb.

If you have rebuilt a carb before then rebuild this one. If not, a 4 barrel is a wee bit much to chew on for a first time rebuild. Using a factory manual and a digital camera to take pictures of the carb dismantling will help with reassembly. The carb probably needs a complete teardown, a good soaking in carb cleaner solution then blown dry w/compressed air. Get a MERC. CARB KIT and use the specs. from the Merc. manual. You can get it from eBay cheap or download it free; search the threads for it. Your computer will need 2 gigs of RAM to handle the huge file; it can take up to 30 mins. to download.

If you buy a Merc. reman. carb, use the metal tag on the carb for reference to get the right carb. Put the metal tag on the replacement carb."
 
"Hey, On the Pushbutton switch

"Hey, On the Pushbutton switch can I used a 16 guage wire. Will this be ok or do I need a 14 guage. Thanks
be blessed tracy"
 
"Rod said that he used a 14 ga

"Rod said that he used a 14 ga wire to go back to the fuel pump. I certainly would'nt go any smaller than that. Put a #12 in there just to make sure its big enough. When you only have to buy one small roll of wire, cost isn't a factor. But when you a doing a job like this, too small of a wire is a factor. I checked out the wiring diagram to see what Rod did, and it looks good, sounds like it should work. Solder those wires on and used heat shrink where you can. No crimp on connectors in this watery environment.

Wrench"
 
"Tracy;
Like wrench says, use

"Tracy;
Like wrench says, use nothing smaller than 14 guage.
You can make the connection to the pur/yell wire right at the terminal at the starter solenoid. This avoids splicing into the engine wiring harness. This is how I did it.

Rod"
 
Hey guys I posted early but it

Hey guys I posted early but it never showed up so trying again.

Today I finished the primer switch on the fuel pump. It work but a few questions and concerns. The fuel pump never shut off as long as the button was held. What could the problem be there. We held the button for apprx a min waiting to see if it would shut off. Never did. Another thing I notice was the Choke slowly started to open while priming the fuel pump. Whats the problem there?

All help greatly appreciated thanks to everyone
Be Blessed
Tracy
 
"Tracy...

When you provide

"Tracy...

When you provide power to the purple/yellow wire at the starter, it connects power to...

1) fuel pump
2) oil pressure switch
3) electric choke cap

There is no problem with the wiring. But the longer you hold that push button on, the farther that choke will open up. Then there will be no choke action to start the cold motor. Like Rod said, hold in the push button for a few seconds, try about 5, then let it off and try to start the motor. Experiment with it a little until you get the routine down pat. You need to have that choke working, don't hold it on so long.

Wrench"
 
"Ok now I know the cold starti

"Ok now I know the cold starting problems is basically fixed Next question?

Should I focus on the empeller next or the carb rebuild?

On ordering the carb this is the number is found on it 9666S 1121.
Where would be the best place to go.
The Boat shop wants $227.00 for the weber rebuid kit.

Is this the correct one at this link
I/O CARB KIT 18-7748
http://www.marineengine.com/parts/sierra_marine/catalog.html?[url]http://www.marineen gine.com/parts/sierra_marine/sierra00609.htm[/url]

Or will this off ebay work.
weber 4 bbl overhaul kit 823728 quicksilver

http://cgi.ebay.com/ebaymotors/weber-4-bbl-overhaul-kit-823728-quicksilver_W0QQi temZ280281035325QQcmdZViewItem?_trksid=p4506.m20.l1116


The boat shop is also they are saying I only need to get the empeller and 2 gaskets. But I'm seeing actual water pump kits online. Just replacing the empeller seems to good to be true. Should I just plan on getting the kit?

Also this is whats on the back of my stern
4.3 LX GEN +
Alpha One
Eng Serial # OK19489
Transom OK231203
Drive Serial OK247024
So When ordering this kit does GEN + Stand for generation 1 or 2?
I know these are alot of probably simple questions but I figure sometimes asking alot of questions are better than not. Thanks for all the help.
Be Blessed
Tracy"
 
"PN: 835076 This number is t

"PN: 835076 This number is the Merc. kit you need. Click on Engine Parts above and insert the PN in the search box. See item #1 in the site below. Item #6 PN: 811536T is the float if you need new ones. If you have brass floats, shake them to make sure they don't have pin holes in them; replace them if there is fluid in them.

http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=809969%2096&ivar=images/C RUISER/809969.96/9.png&inbr=1937&bnbr=100&bdesc=CARBURETOR+%28WEBER%29"
 
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