Can’t get my boat engine to start

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Nov 18, 2018
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I’m having trouble getting my boat to start. It’s a 1999 Volvo Penta 4.3GLPWTR V6. I changed the spark plugs, distributor cap, and rotor and started the boat up just fine and it ran fine. I put the throttle down a little and noticed my prop wasn’t spinning so I shut the boat off and pulled the outdrive off my boat. I got the outdrive repaired and I put it back in my boat. Went to start it up to test the outdrive and now the boat won’t start. The engine will turn over but not start. I checked the spark plugs and I’m getting spark. I checked the fuel pump and that is working fine. When I prime the engine to start it I can look down into the carb and see the fuel being dumped into it. I checked the fuel filter/water separater and there was no water in it. Tried spraying starting fluid on the carb and it still won’t start. When I do that I get the engine to putt a couple times when I’m cranking it but it won’t start. I dumped fresh gas in the top of the carb and I could get it to putt a couple times again but not start. So it shouldn’t be bad gas since the fresh Thought maybe I fouled the plugs so I replaced the spark plugs again but that didn’t change anything. The only thing that changed when I had it running last was taking the outdrive off and had it repaired and then put back on. That shouldn’t be why the engine won’t start. So I’m getting spark and gas. I don’t know what else to try. Any ideas?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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welcome aboard

are your batteries fully charged? if the motor doesnt spin fast enough, it wont start.
 

aimlow

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I’m having trouble getting my boat to start. It’s a 1999 Volvo Penta 4.3GLPWTR V6. I changed the spark plugs, distributor cap, and rotor and started the boat up just fine and it ran fine. I put the throttle down a little and noticed my prop wasn’t spinning so I shut the boat off and pulled the outdrive off my boat. I got the outdrive repaired and I put it back in my boat. Went to start it up to test the outdrive and now the boat won’t start. The engine will turn over but not start. I checked the spark plugs and I’m getting spark. I checked the fuel pump and that is working fine. When I prime the engine to start it I can look down into the carb and see the fuel being dumped into it. I checked the fuel filter/water separater and there was no water in it. Tried spraying starting fluid on the carb and it still won’t start. When I do that I get the engine to putt a couple times when I’m cranking it but it won’t start. I dumped fresh gas in the top of the carb and I could get it to putt a couple times again but not start. So it shouldn’t be bad gas since the fresh Thought maybe I fouled the plugs so I replaced the spark plugs again but that didn’t change anything. The only thing that changed when I had it running last was taking the outdrive off and had it repaired and then put back on. That shouldn’t be why the engine won’t start. So I’m getting spark and gas. I don’t know what else to try. Any ideas?

Time for a professional.

Why would the prop spin in neutral?
 

alldodge

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Maybe flooding or not getting spark consistently, or high enough. Check the rotor to see if it is turning when cranking. Then place a timing light on the coil wire and see if your getting consistent flashing. Watch the tach to see if it shows around 300 rpm while cranking. If good pull some plugs and see if they are wet.
 

aimlow

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Nov 7, 2018
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Maybe flooding or not getting spark consistently, or high enough. Check the rotor to see if it is turning when cranking. Then place a timing light on the coil wire and see if your getting consistent flashing. Watch the tach to see if it shows around 300 rpm while cranking. If good pull some plugs and see if they are wet.

IS that a carbureted engine?? Which carb?
 

aimlow

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Its a GL which makes it a carb, and the Volvo Penta 4.3GLPWTR makes it a 2bbl Holley

Thanks..I don't really follow Volvo's nomenclature.

So if it ran before the work, it's probably something to do WITH the work. Firing order on the cap or plug wires? Turn the distributor and get the timing off?
 
Joined
Nov 18, 2018
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Scott Danforth. The barriers are charged. I just bought a brand new one a couple months ago.


Alldodge. I will have to check to see if the rotor is spinning but I am getting spark when I pull the spark plugs out and turn the engine over. Some of the spark plugs are wet when I pull them out


Aimlow. After I changed the spark plugs, distributer cap and rotor the boat started right up and it ran for a few minutes before I shut it off to look at the outdrive. It shouldn’t have started after I replaced those things if there was something wrong with that.
 

alldodge

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Plugs wet, your flooding and it normally won't start. Need to rebuild the carb
 

aimlow

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Aimlow. After I changed the spark plugs, distributer cap and rotor the boat started right up and it ran for a few minutes before I shut it off to look at the outdrive. It shouldn’t have started after I replaced those things if there was something wrong with that.
Absolutely correct...didn't catch that. Neutral safety switch?
 
Joined
Nov 18, 2018
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Alldodge. My plan was to rebuild the carb this winter because I was having some other issues so hopefully this will fix all of my problems. Thank you.

Aimlow. I checked the safety lanyard and that was on right so it’s not that. Going to rebuild the carb and go from there. Thank you.
 

QBhoy

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Strange one this. I was thinking the in gear interlock too, but it’s getting a spark.
What turned out to be wrong with the drive ? Surely nothing on the engine would have been disturbed. Unless something has been knocked or damaged by the mechanic in the process, if he was around the engine.
Does it have an electric fuel pump ? Have a look at that, as well as the auto choke.
 
Joined
Nov 18, 2018
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Strange one this. I was thinking the in gear interlock too, but it’s getting a spark.
What turned out to be wrong with the drive ? Surely nothing on the engine would have been disturbed. Unless something has been knocked or damaged by the mechanic in the process, if he was around the engine.
Does it have an electric fuel pump ? Have a look at that, as well as the auto choke.

The pinion gear was shredded. All of the teeth were gone. I took the outdrive off myself and brought it to the mechanic so they were not around the motor. It has an electric fuel pump but that is working. From everything I have tried the choke stays closed. I have gas in my oil now. I’m thinking the carb needs to be rebuilt. I think the float is stuck open and allowing to much gas to get in the cylinders and it’s leaking into the oil.
 

Maclin

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I think those had Holley Carbs, and the power valves can rupture and dump a couple of fuel bowls worth of fuel directly into the intake plenum floor after shutdown before the residual fuel pressure is relieved. Carb rebuild time.
 

Scott Danforth

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however the carb is after 1992, so there should be an anti-rupture check valve to prevent the power valve diaphragm from rupturing if there is a backfire.

it doesnt mean that a 20 year old fuel system may have other issues. a stuck float would simply pour fuel down the throat. so would a pump output greater than 7psi.
 
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Nov 18, 2018
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If I buy the rebuild kit and rebuild it myself. When I put it back on the motor do I need to make adjustments for the idle and speed or how does that work?
 

aimlow

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If I buy the rebuild kit and rebuild it myself. When I put it back on the motor do I need to make adjustments for the idle and speed or how does that work?

Ewww..if you have to ask these questions, I wouldn't rebuild the carb by myself.
 

alldodge

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If I buy the rebuild kit and rebuild it myself. When I put it back on the motor do I need to make adjustments for the idle and speed or how does that work?

Yes, and not a big issue. Pay close attention to the instructions and how to measure during rebuild. Pay close attention to the small channels in the carb, they need to be clean. Find a thin wire to run thru them.

Once done, turn idle screws (gently) all the way in, then back out 2 1/2 turns. This will be a good place to start the dile mixer adjustment. Get the motor warmed up, set idle and adjust/check timing.

Once there turn the mixer screw in one at a time no more then 1/4 turn each time. Let motor settle and continue in (1/4 at a time) until the motor starts running rough, not where it is and back out 1/4 turn. Now turn the other screw the same way as first.

Make sure idle is at correct rpm and you should be good for a water test
 

Jake2603

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Sep 22, 2018
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If it's an aftermarket electric fuel pump it's probably between 5 & 8psi (automotive standard). You'll need a fuel pressure regulator added in-line and set between 3 & 5 psi. You can buy the Mr. Gasket or Holley for around $30, either of them work fine. If you purchase the Holley you will also need to buy a gauge, the Mr. Gasket has the settings embossed.
 

TrevorStott

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I saw something about the prop spinning in neutral... Is it possible that when you reinstalled the outdrive that you somehow have the outdrive stuck in gear? That could cause issues with starting...
 
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