She just won't start easy nor stay running 4.3l

[beruken]

Without getting into the issue of why my boat won't start yet, how does the electric fuel pump work? It looks like power is supplied from the the starter. but i don't know when power is actually turned on to the pump. Going further into this, I put a volt meter under multiple conditions to the black and purple/white and nothing. Checked the resistance on the P/W and it was reading 10 ohms???? Can someone enlighten me what should happen when I first turn the key on or pump the gas prior to start?

btw, I replaced the starter due to a broken post on the solenoid/relay where the battery wire connects. I believe everything was back as intended. Can't read the damn schematics merc prints.

4.3 LH 190 Cuddy

 

[beruken]

So i just decided to pull the fuel line and turn the key and gas was pumping out so not my problem. However, boat won't start very easy nor stay running. Back story, sat for 4 years. Rebuilt carb during that time and tried to start last summer and it fired right up ran fine with 3 y/o gas treated a couple years. No exhaust manifolds so i shut it down. tried again in the fall prior to closing it up for the winter and nothing. Now I've been trying again to get it in the water so i was back at it this spring. It just would not fire. Removed all the old gas and put on a new fuel filter still nothing. Finally I tried WOT from a post here and it eventually started but struggled to keep it running. I think maybe the carb is gummed up but the gas didn't seem bad and i used it mixed in my cars. When I can get it to start it seems like it is loosing fuel and stalls. Thoughts? I'm ready to pull apart the carb again and try cleaning it out.

 

[beruken]

Opened carb and something was floating in it. Seemed a little dirty so cleaned it out and tried again. Nothing. I'm at a loss.

 

[alldodge]

The fuel pump runs when key is turned to start thru the starter. Once motor starts and oil pressure builds and power is applied to keep pump running


After 4 years your gas is probably bad.
Remove the fuel filter and dump contents into a clear container to see if there is nothing but clean gas

Use gas can with fresh gas and length of fuel line. Connect fuel line to fuel filter. Prefill filter with gas and try to start

Measure power at the + side of coil with key ON motor off, and also while cranking

Get a spark tester and check for spark.

 

[beruken]

The fuel pump runs when key is turned to start thru the starter. Once motor starts and oil pressure builds and power is applied to keep pump running
View attachment 399503

After 4 years your gas is probably bad.
Remove the fuel filter and dump contents into a clear container to see if there is nothing but clean gas

Use gas can with fresh gas and length of fuel line. Connect fuel line to fuel filter. Prefill filter with gas and try to start

Measure power at the + side of coil with key ON motor off, and also while cranking

Get a spark tester and check for spark.

Thanks. I already did all that. Post carb cleaning it would still not start again. Was hoping it was the problem. Even starter fluid is not helping. I did notice the only time gas had spurted out of the line was when I pumped the throttle.This was an engine that never failed me. Even after the carb rebuild it had fired first time and ran fine. Frustrating as I'm loosing good days. I'm going to try again now and run thru all the obvious.

 

[alldodge]

OK fuel is good so spark is not

 

[cyclops222]

Post pictures of the sparkplugs ? Condition of them ? Full of black stuff ?
What year is it ? Did Mice crawl into the open exhaust ports ? And die in there ?
Can yo post Compression readings ?

 

[beruken]

Post pictures of the sparkplugs ? Condition of them ? Full of black stuff ?
What year is it ? Did Mice crawl into the open exhaust ports ? And die in there ?
Can yo post Compression readings ?

I was just about too. Got it to fire and it blew out flames and fuel but then burped hard and shot out a large flame. tried again and it started and got it to idle for about 15 sec then died. pulled 2,4 and 6 plugs. Looked black sooty. the pic looks rusty but it was black to my eye. I did leave the boat sitting with shop paper towels stuck in the exhaust ports for a few years so, yeah, probably got some gunk in the cylinder walls

 

[beruken]

Post pictures of the sparkplugs ? Condition of them ? Full of black stuff ?
What year is it ? Did Mice crawl into the open exhaust ports ? And die in there ?
Can yo post Compression readings ?

I don't believe so. No on the readings but i'm going to go to autozone and get a tester.

 

[alldodge]

I was just about too. Got it to fire and it blew out flames and fuel but then burped hard and shot out a large flame.

It is fuel and/or timing is way out of range
Old fuel is bad and can cause many things way out of range but back firing is timing or bad fuel

 

[beruken]

It is fuel and/or timing is way out of range
Old fuel is bad and can cause many things way out of range but back firing is timing or bad fuel

Well as noted I replaced all the fuel and new filter. I was thinking the same wrt timing but I never did anything to it from last summers startup to fall when it first would not start. I didn't even run the boat as I had my outdrive in pieces for 4 years and no exhaust manifolds. No time to get compression tester but did pull all the plugs cleaned and it fired into an idle momentarily then stalled again. I'm wondering if it's flooding but the plugs are not all wet. Just sooty.

 

[Dillusion808]

Don't assume anything when troubleshooting.
Set that timing again. I'd also change the plugs instead of just cleaning its cheap.

I've had the same issue before. I'd admit I didn't check timing before hand but it was running. Went out one day and started at the launch then died and could not get it re-started. Did all the basic checks and re-did the timing and fired right up.

 

[Lou C]

Also if it’s back firing thru the carb you might have an intake valve that’s hanging open or not closing all the way. Any water in cyls after running?

 

[beruken]

Also if it’s back firing thru the carb you might have an intake valve that’s hanging open or not closing all the way. Any water in cyls after running?

Hey Lou, I don't believe so. No indication on the plugs of water. I think that was a one time burp with all the fuel and engine starter I had dumped in it.

 

[Scott06]

Hey Lou, I don't believe so. No indication on the plugs of water. I think that was a one time burp with all the fuel and engine starter I had dumped in it.

the boat sat for four years and now it is back firing? Why was the exhaust off? If leaking valve may be hung up. Worth starting with compression test based on sitting

 

[beruken]

Don't assume anything when troubleshooting.
Set that timing again. I'd also change the plugs instead of just cleaning its cheap.

I've had the same issue before. I'd admit I didn't check timing before hand but it was running. Went out one day and started at the launch then died and could not get it re-started. Did all the basic checks and re-did the timing and fired right up.

How do I preset the timing without a running engine?

 

[beruken]

Update: put new plugs in and cleaned and re-seated the coil connection. Took out plugs to do a compression test and one specifically was wet the others smelled of fuel. Not sure if that was due to turning the engine over once before testing. Compression was between 158 and 180 so I believe it hit all it's requirements. Spark with one plug showed bright orange but not quite the white/blue I was expecting.

After the test, without fuel pump connected. tried to start it and it immediately gave a small bump but then nothing. I think the carb is part of the problem even after rebuild. First time testing rebuild it started immediately and ran good last summer. then nothing the next time I tried in the fall. Waiting on a new carb cheapo and ignition coil.

 

[Dillusion808]

How do I preset the timing without a running engine?

Its just setting initial timing. Its not going to be perfect but should get it running if everything else is working.
What I did in a nut shell.

1. Rotate the engine to TDC on the Compression Stroke of the #1 cylinder.
   1. Both valves should be closed.
2. Install the Degree Wheel on the crankshaft and set it to zero.
3. Turn the crank backwards until the degree wheel reads 10 degrees BTDC.
4. Align the distributor rotor with the cap location for the #1 spark plug wire.
5. Line up the magnetic pickup with the reluctor.
6. JUST SLIGHTLY rotate the distributor backwards from the normal direction of rotation.
   1. The contact points should be barely misaligned.
7. Install the distributor and tighten it down.

I've never touched my timing before this. But one day the motor would just not start. I checked everything fuel, spark, all my wiring and voltages and I was stumped.

Threw a hail mary and just redid the timing and she fired right up.

I could of hit the distributor while working in the bilge but who knows.

 

[alldodge]

Being a 4.3 LH and not having a serial number the motor "should" have TBV ignition. Would know better with serial number

TB4 or 5 has same troubleshooting chart


Being TB ignition it might be the module, but test should verify.
Does the module have 2 or 3 wires on it?

 

[beruken]

Its just setting initial timing. Its not going to be perfect but should get it running if everything else is working.
What I did in a nut shell.

1. Rotate the engine to TDC on the Compression Stroke of the #1 cylinder.
   1. Both valves should be closed.
2. Install the Degree Wheel on the crankshaft and set it to zero.
3. Turn the crank backwards until the degree wheel reads 10 degrees BTDC.
4. Align the distributor rotor with the cap location for the #1 spark plug wire.
5. Line up the magnetic pickup with the reluctor.
6. JUST SLIGHTLY rotate the distributor backwards from the normal direction of rotation.
   1. The contact points should be barely misaligned.
7. Install the distributor and tighten it down.

I've never touched my timing before this. But one day the motor would just not start. I checked everything fuel, spark, all my wiring and voltages and I was stumped.

Threw a hail mary and just redid the timing and she fired right up.

I could of hit the distributor while working in the bilge but who knows.

wow, I bought a timing lite, figured that may help while cranking the engine Thanks! I had the same problem a few years ago as well and didn't understand why the engine was cranking without charging the battery for so long. Bought a new everything including ecu. finally put some jumper cables on the battery and BAM!, the damn thing started. Go figure.