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1996 5.7l with Thunderbolt 5; starting hard

J

Jeff88

New member
My 1996 Searay has a 5.7l with Thunderbolt 5 ingnition.
It does not start at the touch of the key, but rather cranks and eventually fires.
I pump the throttle once before starting cold.
It runs great once it starts.
Even when it is warmed up, it usually doesn't fire immediately, usually requiring increasing throttle above idle.
I'm thinking the ignition components my be tired.
I believe I cleaned the cap/rotor two seasons ago, but have not replaced anything since buying the boat (4 years).
The plugs look great. Timing tests ok.
Does this sound like an ignition system issue (rather than carb/fuel), and if so, should I replace anything else besides the usual points, cap, rotor?
How about coil or ignition sensor (not cheap parts)?
 
thinking you need to pump it 2 or 3 times if the accelerator pump is getting weak .I`m sure the TB-V is putting out plenty of sparkpower. After 4 years I think a new cap and rotor would be nice. Has the drive also not been serviced in 4 years?
 
Jeff88 said:
My 1996 Searay has a 5.7l with Thunderbolt 5 ingnition.
It does not start at the touch of the key, but rather cranks and eventually fires.
I pump the throttle once before starting cold.
It runs great once it starts.
Even when it is warmed up, it usually doesn't fire immediately, usually requiring increasing throttle above idle.
I'm thinking the ignition components my be tired.
I believe I cleaned the cap/rotor two seasons ago, but have not replaced anything since buying the boat (4 years).
The plugs look great. Timing tests ok.
Does this sound like an ignition system issue (rather than carb/fuel), and if so, should I replace anything else besides the usual points, cap, rotor?
How about coil or ignition sensor (not cheap parts)?
Click to expand...

Ayuh,.... Sounds like a Fuel delivery problem,.... What carb is it,..??
 
Regarding the Drive, I had it off last year to replace all of the boots.
The carb. is only a 2 brl., if there are more than one option, I don't know which.
 
Jeff88 said:
My 1996 Searay has a 5.7l with Thunderbolt 5 ingnition.
It does not start at the touch of the key, but rather cranks and eventually fires.
I pump the throttle once before starting cold.
It runs great once it starts.
Even when it is warmed up, it usually doesn't fire immediately, usually requiring increasing throttle above idle.
I'm thinking the ignition components my be tired.
I believe I cleaned the cap/rotor two seasons ago, but have not replaced anything since buying the boat (4 years).
The plugs look great. Timing tests ok.
Does this sound like an ignition system issue (rather than carb/fuel), and if so, should I replace anything else besides the usual points, cap, rotor?
How about coil or ignition sensor (not cheap parts)?
Click to expand...

I said that a cleaning and kit might do you good. See in bold above. You might try two pumps of the throttle next time when the engine is cold. Here's a few other things:
- Is your electric choke working correctly,
- Is the flame arrest-er clean,
- When 's the last time it was fully warmed up, in the water, idling in neutral, and the air fuel adjustment screws and idle screw adjusted.
Stay in touch and good luck. Rick
 
Thanks for the input Rick.
The Carb hasn't been touched since I bought the boat 4 yrs ago.
Except for a couple of motorcycles, I haven't messed with a carb. for quite a few years, so I'm gonna have to get a friend to help.

You also mentioned the electric choke. Is there a simple test/procedure to confirm if it is functioning as it should?
 
Jeff88 said:
Thanks for the input Rick.
The Carb hasn't been touched since I bought the boat 4 yrs ago.
Except for a couple of motorcycles, I haven't messed with a carb. for quite a few years, so I'm gonna have to get a friend to help.

You also mentioned the electric choke. Is there a simple test/procedure to confirm if it is functioning as it should?
Click to expand...
Well, there is a resistance measurement to prove the t-stat is good but, another way would be for you to remove flame arrester, pump throttle once, turn the key on......but don't try to start it of course. Choke should be closed, but after a few minutes, it should open completely. Make sense?
 
It might not be an electric choke but a manual that's activated by a coil that expands to open with heat.
With the flame arrest or off, you should see a closed butterfly valve that you can push on to open manually
with the engine cool. It should completely closed. If not, it either needs adjusting or replacement.

You might also "pump" on the throttle while looking inside the Venturi or top of carb without running. You should see the accelerator pump spraying fuel into the center of the Venturi.

As others have said above, if the accelerator pump is bad, it's harder to start but would also stumble a bit on hard take offs.

Good luck.
 
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