Hello all, bought a 1996 330 Sundancer with twin carburated 7.4L 454s that ran great, now that is cold here the port engine cranks strong but will not start, almost like it’s not getting fuel. Has anyone experienced this? Not sure where to start. Thanks for any leads.
Engine won’t turn over
- Thread starter Lou R
- Start date
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- Tags
- engine cranks
Espos4
Well-Known Member
Does the choke plate close when you advance the throttle?
Do you see fuel squirt into the venturi from the accelerator pump when you advance the throttle?
Do you see fuel squirt into the venturi from the accelerator pump when you advance the throttle?
I have to go back and look at the carb while I try to start it.
When I crank it, I should see fuel squirting into the ventury and the chock plate should be closed?
Should I use starting fluid to see if that’s the problem?
When I crank it, I should see fuel squirting into the ventury and the chock plate should be closed?
Should I use starting fluid to see if that’s the problem?
Espos4
Well-Known Member
When you advance the throttle, the choke plate should close (if it isn’t closed already) and fuel should squirt into the Venturi. The faster you advance the throttle, the more fuel will squirt.
You may have to hold the choke plate open to see the fuel squirt in.
If you don’t have fuel, then yes starting fluid can help it start.
If it’s been sitting for a while, the fuel in the carburetor bowl may have evaporated or drained down. If that’s the case, it’ll need a little extra cranking to refill the fuel bowl before you see any activity from the accelerator pump.
You may have to hold the choke plate open to see the fuel squirt in.
If you don’t have fuel, then yes starting fluid can help it start.
If it’s been sitting for a while, the fuel in the carburetor bowl may have evaporated or drained down. If that’s the case, it’ll need a little extra cranking to refill the fuel bowl before you see any activity from the accelerator pump.
Hoplite808
Well-Known Member
- Jan 11, 2022
- 507
- Boat Info
- 1996 Sea Ray 270 Sundancer
- Engines
- Mercruiser 7.4 LX MPI EFI (Gen. V)
@Can’t Wait spray a bit of starting fluid down the carb and then try and start it. If it kicks over and tries to run on that you know it’s a fuel problem and not an ignition problem.
If you determine it’s a fuel issue check if fuel is coming through the line while it cranks by disconnecting it from the carb and dropping the fuel line into a cup or small bucket. If fuel is flowing then it’s likely the carb has a stuck needle valve and you’ll have to take apart the carb and clean and rebuild it.
If there is no fuel flow then check the pump. If the pump is fine then it’s possible the fuel pickup in the tank is having an issue.
Also if the starting fluid starts it and it starts to run on its own without more starting fluid it’s likely that your choke is out of alignment. Or the electric part of the mechanism has failed.
If you determine it’s a fuel issue check if fuel is coming through the line while it cranks by disconnecting it from the carb and dropping the fuel line into a cup or small bucket. If fuel is flowing then it’s likely the carb has a stuck needle valve and you’ll have to take apart the carb and clean and rebuild it.
If there is no fuel flow then check the pump. If the pump is fine then it’s possible the fuel pickup in the tank is having an issue.
Also if the starting fluid starts it and it starts to run on its own without more starting fluid it’s likely that your choke is out of alignment. Or the electric part of the mechanism has failed.
markrsimon
Active Member
Figure out if you have a manual/spring operated choke or an electric choke. The spring type literally has a coil mounted to the top of the intake manifold with a small linkage connecting it to the carb. The electric ones are round and stuck to the side of the carb.
For the old school coil ones, you normally need to set the choke. Before you try to start, take the throttle and advance it all the way (full throttle) and return to idle. This causes the choke plate on the carb to close. Also when you do that, it pushes the accelerator plunger down - which as stated above - squirts gas into the engine.
If the choke plate doesnt close - it will be much harder to start.
If its been a few days (4-5) since you ran the boat last - you may need to crank more to help get fuel into the carb. Crank for 10sec and stop. Then advance throttle fully again (think accelerator pump - and squirting fuel into engine) and return to idle. Try starting again. Sometimes it helps to advance the throttle a bit - and as soon as it starts back the throttle down quickly. May need to repeat crank/throttle/start procedure a few times.
For the old school coil ones, you normally need to set the choke. Before you try to start, take the throttle and advance it all the way (full throttle) and return to idle. This causes the choke plate on the carb to close. Also when you do that, it pushes the accelerator plunger down - which as stated above - squirts gas into the engine.
If the choke plate doesnt close - it will be much harder to start.
If its been a few days (4-5) since you ran the boat last - you may need to crank more to help get fuel into the carb. Crank for 10sec and stop. Then advance throttle fully again (think accelerator pump - and squirting fuel into engine) and return to idle. Try starting again. Sometimes it helps to advance the throttle a bit - and as soon as it starts back the throttle down quickly. May need to repeat crank/throttle/start procedure a few times.
Thank you very much, this is very helpful. I will try those things, I think it’s most likely the choke. I remember the guy that sold me the boat saying that the mechanic forced the choke to stay open somehow to get better gas mileage. I should have enquirer more about it at the time but I didn’t.
BarryCF
Active Member
Ouch on the choke. Cold weather starting requires the choke to operate properly. If the mechanic disabled it to "get better gas mileage" he wasn't much of a mechanic..
HardHead
Member
- Jan 9, 2015
- 77
- Boat Info
- 1996 Sea Ray 370 Sundancer
Previous boats:270 Sea Ray, 230 Sea Ray
- Engines
- Twin 454 Mercruiser Inboards
I have the same motors with carbs in a 96 370. Last year I had the same issue with my port engine. Turns out it was the manual fuel pump, the spring broke. Just pour a little gas into carb. If it runs then dies it's most likely the pump. If it runs after this it may have been a vapor lock on the fuel side.
Good Luck
