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Digging into a 20 year old 4.3L for the first time

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BassAckwards

Contributing Member
Hello, just joined this forum, great group of folks out here! I just picked up my '95 Sea Ray BR. Needs some cosmetic work, but the engine seems to be in somewhat well cared for condition, and I couldn't beat the price. Good service records it seems, so I took the risk.

Anyhow, I just thought I'd start a thread on the process of taking this motor down the path to something that I could trust to take my family a few miles off shore with.

So far I have replaced the engine oil, and drive gear oil, and had her out for 2 test runs. Both times she starts and idles beautifully, but after about 10 mins of half throttle ( haven't opened her up yet) she sputters out and dies. She limps me back to the dock, but won't allow me to accelerate unless she gets a rest first.

I'll list some symptoms/issues and what I'm up to so far. I've never worked on much more than a 50hp Johnson before, so any help steering my repairs in the right direction would be awesome.

Temp gauge never moves. However, when run on muffs for long periods, the water never seems to get more than just lukewarm. Im suspicious of the thermostat and the temp sender, so I'll look to replace both.

Speedo doesn't work. I'll check the OD for clogged input.....once I find where that is....

I've ordered a Carb ( 2bbl Mercarb ) rebuild kit from 'Mike's Carbs' and a new float. That should be fun putting that in.

I haven't pulled the plugs or checked cap/rotor yet.

She needs a new blade...old one is pretty chewed up. There seems to be real science behind picking these so I'll probably just go down the middle with a 21deg replacement.

What critical checks should I make before taking her out for a long run? Is there a good checklist or thread that has links to instructions for such a thing? Thanks Everyone and I look forward to sharing my new toy with ya'll. ... and hopefully some fish pictures :)
 
and had her out for 2 test runs. Both times she starts and idles beautifully, but after about 10 mins of half throttle ( haven't opened her up yet) she sputters out and dies. She limps me back to the dock, but won't allow me to accelerate unless she gets a rest first.
Click to expand...

Ayuh,.... Welcome Aboard,.... Sounds like it's runnin' outa gas,....

Probably the boat side of the fuel system,....

Run it on a remote tank of fresh clean gas, 'n see what it does,...

'n check the Contents of the fuel filter for water, 'n crud,...
 
bondo said:
Ayuh,.... Welcome Aboard,.... Sounds like it's runnin' outa gas,....

Probably the boat side of the fuel system,....

Run it on a remote tank of fresh clean gas, 'n see what it does,...

'n check the Contents of the fuel filter for water, 'n crud,...
Click to expand...


Ah, the filter... I haven't changed it yet ( and I have a replacement ). That's a quick one I can do while I wait for the carb kit. Thanks!
 
There are two efficient speeds of which to operate at......... hull speed and planing speed.
Planing speed is best when just above the speed required to get the hull up on top of the water.

Any speed in between these may over-burden your engine, and it will most certainly waste fuel.

While at half throttle only (again, between hull speed and efficient planing speed), the engine may be struggling, resulting in high cylinder temperatures.
High cylinder temperatures are a prelude to Detonation.
Detonation can and will cause mild to severe issues.

I'm certainly not discounting the fuel or fuel filter related possibilities.

As suggested...... change the fuel filter.
Look at spark plugs.... change plugs/wires, etc. if need be.
Look at what the ignition advance is doing..... not just BASE advance.... we're talking about the progressive and TA.
Monitor engine temp accurately and carefully.

Do what's necessary to prevent over-burdening your engine.




.
 
Timing...wow.... I haven't had a timing light in my tool box for about a decade. Do they still make those things? Hoping old Wally world still has them lying around.
 
First off if you did not adjust the timing then for now don't worry about it.................WTF! NOT YOUR PROBLEM!


You may want to look at your pistons and make sure they are of the Q/E type and have a TA for the OP...

Maybe the KF and RQ is out..........OMG!! Here we go again!






Back to your issue.......................


Fuel related problem as suggested,

either bad or lack there of.......either carb is in need of rebuild ( very likely) and/or filter bad, clogged (should replace anyway).

Pull the plugs and check them as a minimum see what they look like and replace if needed.

Also if the boat sat for a very long time find the fuel vent, it MUST be clear of debris and spider webs and of course spiders. Either remove from the tank side and blow it out with some compressed air or simply blow back into the tank from the outside BUT if there is anything there it may end up in the tank.

If the vent line is clogged it will create a vacuum on the tank and stop fuel flow it could take a while for this to show up based on how much fuel is in the fuel is in the tank.

After your fuel issue is resolved get back to us and let us know if any other issues are present.
 
I don't believe that it's good advice to suggest that you NOT look at ignition advance, nor to suggest from a keyboard that it's not your problem.

I would check it, and either find that it's incorrect (and is causing part or all of your issue)......., or eliminate it from your P of E list.


.
 
So, I've rebuilt the carburetor, reinstalled it. Set the choke. Replaced the fuel filter/water separator, and I 'm not getting any fuel at all to the carb. She'll try to start on ether, but if I disconnect the fuel line from the carb there isn't a drop in there. When I push the throttle there is nothing coming from the jets.

*updated* I pulled off the filter and it was bone dry. No fuel is pulling into the filter. I prefilled it and still not making progress. Tank vents look good.

When I turn the key, I hear sound like a fuel pump charging up near the fuel filter. It shuts off after a minute and runs for a second after each attempt to start. No fuel is getting to the carb though. Is there something I need to reset??
 
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.......................

BassAckwards said:
So, I've rebuilt the carburetor, reinstalled it. Set the choke. Replaced the fuel filter/water separator, and I 'm not getting any fuel at all to the carb. She'll try to start on ether, but if I disconnect the fuel line from the carb there isn't a drop in there.
Inoperative fuel pump?????

When I push the throttle there is nothing coming from the jets.
You may be thinking about the accellerator pump nozzles. An Engine must be running in order to see fuel being delivered from jets or fuel metering ports.

In any event, for this to occur (or I should say to NOT occur), the fuel bowl must be empty or dang near empty.
I's suggest that you revisit your fuel delivery issue.


*updated* I pulled off the filter and it was bone dry. No fuel is pulling into the filter. I prefilled it and still not making progress. Tank vents look good.
This is why I suggested "revisit your fuel delivery issue."
IMO......, Replacing a fuel pump (if it has NOT been replaced recently), is never a bad idea!

When I turn the key, I hear sound like a fuel pump charging up near the fuel filter.
You should NOT be hearing an electric fuel pump operating by simply turning the key to the ON position.
1...... There should be a N/O LOP switch that would prevent fuel pump operation until the Engine firese up and achieves oil pressure.
2...... There should also be a "start-by-pass" circuit that will momentarily operate the fuel pump.... but only during starter motor action!

It shuts off after a minute and runs for a second after each attempt to start. No fuel is getting to the carb though. Is there something I need to reset??
Find your OEM work shop manual and read up in the "trouble-shooting" section.
Click to expand...
 
Last edited:
BassAckwards said:
So, I've rebuilt the carburetor, reinstalled it. Set the choke. Replaced the fuel filter/water separator, and I 'm not getting any fuel at all to the carb. She'll try to start on ether, but if I disconnect the fuel line from the carb there isn't a drop in there. When I push the throttle there is nothing coming from the jets.

*updated* I pulled off the filter and it was bone dry. No fuel is pulling into the filter. I prefilled it and still not making progress. Tank vents look good.

When I turn the key, I hear sound like a fuel pump charging up near the fuel filter. It shuts off after a minute and runs for a second after each attempt to start. No fuel is getting to the carb though. Is there something I need to reset??
Click to expand...

Ayuh,.... Hook up a remote tank to the fuel filter, 'n try it,....

If ya get fuel, the problem is in the boat's side of the fuel system,...
Probably a clogged fuel outlet,.....
 
You replaced the fuel/water separator.

If so did you pre fill it with gas?

The pump may not be able to overcome the air in the filter so filling it with gas (and be very careful!!!!!) may help the lack of fuel so do this and retry.

report back on this first and if this is not the issue more advice can be given...

The fuel pump will not or should not run when you simply turn the key to the ON/run position.

The electric fuel pump power is controlled by a oil pressure switch (located just above the oil filter). This pressure switch will not close until a certain amount of oil pressure is present. ~ 5 -10 psi ( I forget the exact amount)

When you crank the motor over there should be 12 volts which bypasses the oil pressure switch coming from the starter solenoid. This applies power to the pump during cranking only.
 
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Good info. I mentioned earlier that I prefilled the filter, and no progress noted. I'll try the remote tank step, that should eliminate any issues with the tank. I'll check for voltage at the pump when the key is turned as well. these pumps ( 861155A6 ) run about $250-300 for a decent one it seems. Hoping the issue is otherwise..... Thank you all for the continued follow up!
 
You will NOT have voltage at the pump with the key on.

Only when cranking...........


So here are some trouble shooting suggestions.

YOU MUST BE VERY CAREFUL WHEN DOING THESE!!!!

1. Find the oil pressure switch above the oil filter.

There will be two purple with yellow wires going to the switch. Pull them away from the switch and make a jumper and connect them together. This will bypass the pressure switch (ONLY TEMPORARY!!!!). This will now give you power to the pump when the key is in the on position.

2. USE EXTREME CAUTION!!!!!! Loosen the fuel inlet fitting at the carb. Place several rags under the fitting. now have a second person turn the key to the on position and watch to see if gas leaks out of the fitting. Of course how loose the fitting is will make a difference as to how much fuel leaks out if any. Again be very careful here when doing this!! This is to see if you have gas flow...........

If there is no gas flow reconfirm you have a full water separator of gas!! If not refill and retry.

If no gas flow then the pump is most likely bad.

Look here for alternatives


http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_1ddyzvvc4s_e

This may be a viable alternative.........

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_1ddyzvvc4s_e

These are only suggestions for replacement. Myself I would replace with a OEM pump or convert to a marine stand alone pump. Also the pump replacement MUST be for a carbed motor!! Max 7-8 psi.
 
.............................

BassAckwards said:
I'll try the remote tank step, that should eliminate any issues with the tank.
Pull your pick-up tube from the OEM fuel tank, and examine it.
Clear it, clean it, or do what ever is necessary to correct fuel flow.
Replace the "anti-siphon" valve, and re-install it.
There is no need to Jerry Rig an external fuel tank..... that would be a waste of time.
If there was a problem with it to begin with, you will have now corrected it!
You will now be DONE, and with NO hassling with an external fuel tank!

I'll check for voltage at the pump when the key is turned as well. these pumps ( 861155A6 ) run about $250-300 for a decent one it seems. Hoping the issue is otherwise..... Thank you all for the continued follow up!
Please find out why your fuel pump operates when the key switch is turned to ON!
As per post #10, this should NOT occur.
Click to expand...
 
RicardoMarine said:
I don't believe that it's good advice to suggest that you NOT look at ignition advance, nor to suggest from a keyboard that it's not your problem.

I would check it, and either find that it's incorrect (and is causing part or all of your issue)......., or eliminate it from your P of E list.


.
Click to expand...
I agree, distributors with mechanical advance can and do get gummed up and sticky from old oil, sludge, whatever, and don't advance properly. Easily checked with a timing light.
 
CASTLE_CAPE said:
I agree, distributors with mechanical advance can and do get gummed up and sticky from old oil, sludge, whatever, and don't advance properly. Easily checked with a timing light.
Click to expand...
.......................................Mute point!!!!!


No mechanical advance.............................Electronic..........................................



If it were the advance he would have fuel at the carb...........................uggggggggggggggggggg!!
 
Yall are a huge help. Lack of daylight got the better of me and I had to clean up till next weekend or work by lamplight. I'll update on the suggestions you have all made at that time. Thanks again!
 
BassAckwards...... your 20 year old 4.3L Engine's ignition system is Merc's Thunderbird.
These are all EST.
EST = electronic spark timing.

Full Ignition advance is given to the position of the distributor housing/triggering device/rotor.
Then via the electronic circuitry and algorythem of the control unit, the spark event is delayed.
The delay is altered as engine speed increases.
IOW, the ole mechanical advancing flyweight system has been replaced with electronics.

...........................................

BTW...... it's Moot Point...... not Mute Point.

(yes.... this is a copy/paste)

Moot and Mute
There is often confusion over the words moot and
mute. Although they sound similar, their meanings are different.
MootAs an adjective,
moot means open to discussion, debatable, or
doubtful.

  • It is a moot point.
    bultick.gif
    (This is the most
    common meaning of moot. Also, moot point is the most common term
    featuring the word moot.)
As an adjective,
moot can also mean of little or no practical value, purely
academic or purely theoretical.

  • It is a moot case.
    bultick.gif
    (It could, for
    example, be a case set up so law students can practise court procedures.)
Although rare, moot can also be used as a verb which
corresponds to either of the meanings above.

  • I intend to moot this issue.
    bultick.gif
    (I intend to
    present this issue for debate.)
  • We ought to moot this issue.
    bultick.gif
    (We ought to render
    this issue purely theoretical.)

Mute As an adjective,
mute means silent, speechless, refraining from
speech, or quiet.

  • Shocked to the core, he was now mute.
    bultick.gif

  • Bonzo looked at the diners from his basket with mute longing.
    bultick.gif

  • It was an eerily mute village.
    bultick.gif

  • The letter P is mute.
    bultick.gif
    (It's not
    pronounced.)
As an noun, mute is
a a person without the power of speech, a button to turn off the
sound, or a device placed on an instrument to deaden the resonance.

  • He is a mute.
    bultick.gif

  • Press the mute.
    bultick.gif



 
fuel pump arrived today. seems you really need to shop around for your parts, as prices are all over the place. I found this listed on a couple marine parts websites for $230. Stopped and napa for something and would you believe they have it in stock?! They wanted $280 for it, but it was in stock. PUlled up Amazon and a couple of the retailers had it for 118 bucks shipped. go figure eh? 3 days later it's in the mailbox. Weekend project! I'll update on how it comes out. hopefully this was the problem. Now I get to have fun adjusting the carb I rebuilt.
 
Fuel pump apparently wasn't the issue. I see threads that suggest to do other testing first, so I guess I should have done that first. If I put 12v to to the pump, fuel pumps into the carb and i can hear the bowl filling. ( also pulled the line off and confirmed ). ( old pump does the same, so now at least I have a good spare eh?). Anyhow, when I turn the key, the pump does not operate. Strange that when I put a volt meter to the pump connector and crank the engine, I get 10 V on the purple wire and 0 volts on the black ( ground I suppose ). Seems like that should drive the pump but I guess the volts are too low. As i'm typing, i am thinking I need to plug the jack into the disconnected pump and see if it runs when I turn the key. IMG_0348.jpg ( bad connector?) I'll do that this morning.

I am suspicious about a couple things however. I accidentally grounded one of the terminals ( PICTURE attached) and got a facefull of sparks. I know..... disconnect the battery and at very least turn off the freaking key....but I forgot to do either. I'm thinking I must have shorted or tripped something because I haven't been able to get her to turn over since I did that. The other thing would be the oil pressure relay. How would I test to see if this is the issue? I recall that when I checked the oil during the original purchase, it was clean like new oil, but about 3 quarts overfilled on the dipstick. I've been planning to drain that out, but haven't yet. could that effect the oil pressure relay from running the pump?
 
Anyhow, when I turn the key, the pump does not operate.
Click to expand...


BA, please read post # 10 again. You should NOT have power to the electric fuel pump by simply turning the key switch to ON.

The starter motor circuit must first be energized, and from that via the Start-by-Pass circuitry, only NOW will the fuel pump see momentary power!
Once engine oil pressure is achieved, the pump will continue to receive power.



.
 
Last edited:
kghost said:
You will NOT have voltage at the pump with the key on.

Only when cranking...........


So here are some trouble shooting suggestions.

YOU MUST BE VERY CAREFUL WHEN DOING THESE!!!!

1. Find the oil pressure switch above the oil filter.

There will be two purple with yellow wires going to the switch. Pull them away from the switch and make a jumper and connect them together. This will bypass the pressure switch (ONLY TEMPORARY!!!!). This will now give you power to the pump when the key is in the on position.

2. USE EXTREME CAUTION!!!!!! Loosen the fuel inlet fitting at the carb. Place several rags under the fitting. now have a second person turn the key to the on position and watch to see if gas leaks out of the fitting. Of course how loose the fitting is will make a difference as to how much fuel leaks out if any. Again be very careful here when doing this!! This is to see if you have gas flow...........

If there is no gas flow reconfirm you have a full water separator of gas!! If not refill and retry.

If no gas flow then the pump is most likely bad.

Look here for alternatives


http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_1ddyzvvc4s_e

This may be a viable alternative.........

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_1ddyzvvc4s_e

These are only suggestions for replacement. Myself I would replace with a OEM pump or convert to a marine stand alone pump. Also the pump replacement MUST be for a carbed motor!! Max 7-8 psi.
Click to expand...

Above my oil filter is only the 2 oil lines. the switch must be elsewhere. regardless, now I have fuel pumping to the carb when I turn the key. Sweet. Problem now is she isn't trying to start so I'm assuming I did something to the ignition. Spark plugs are buried under the manifold so I would need to take the engine compartment apart to get to them. is there an easier way to check for spark from near the distributor? that red button doesn't move when pressed so i'm assuming it isn't tripped.
 
......................
Above my oil filter is only the 2 oil lines. the switch must be elsewhere.
Is this a remotely located oil filter system?
The N/O LOP switch that Jack mentions, will be above the General Motors OEM filter location.

regardless, now I have fuel pumping to the carb when I turn the key.
As said now several times...... that is wrong and it presents a risk.

is there an easier way to check for spark from near the distributor?
High Energy spark is generated within the ignition coil.
Plull the High Tension lead, temporarily replace it with a spark plug wire, and place a known to be good spark plug in the boot.
Make sure that the spark plug body has good contact with a metal portion of the engine.
Remove all fuel vapors that could accidentially ignite.
Very carefully watch for spark events as the engine is being cranked.


that red button doesn't move when pressed so i'm assuming it isn't tripped.
If tripped, you'd see other issues.
Click to expand...
 
I wanted to come back and wrap up this thread, seeing as many of you put alot of effort into your responses which really helped me get to a good place with understanding my engine. I resolved all the electrical issues, and yet the fuel starvation issues continued even after replacing the fuel pump. It turned out that the Sierra pump I obtained, was bad out of the box. I ordered another one while waiting for the return authorization to be 'accepted', and Badabing! She lives! Carb all set up, and she cruises nicely at 50mph down the James River. Now I just have to learn how to bend and shape Acrylic so I can replace the windshield.........but that is a subject for another post :) Thanks again to all who posted and special thanks to the PMs and phone calls. You are the heart of a great forum!
 
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