96 Sundancer 330 DA Throttle problems

giterdnn1

New Member
Dec 6, 2021
4
Boat Info
1996 330DA Sundancer, Garmin 942sxv,
Engines
7.4 Mie V-Drive's
Good Morning,

looked in prior threads and did not see this issue or may not have gone far enough back.

1996 330DA, Twin 7.4Mie V-drive. Yesterday we went out. The both motors would not throttle past 3000RPM "when in gear". When "Not" in gear would max out RPM's like normal.
Looking for direction.
In advance - New bottom paint, new props. Ran just fine a week ago.
 
Did you recently fill her full of fuel and have more than the normal number of passengers onboard?

Bottom clean (are you in super warm water)?
 
Did you recently fill her full of fuel and have more than the normal number of passengers onboard?

Bottom clean (are you in super warm water)?

Bottom is clean, Full of fuel, 2 people, Nothing out of the normal. as I said would throttle 4800+rpm not in gear/neutral, only issue is when "in" gear moving.
 
Bottom is clean, Full of fuel, 2 people, Nothing out of the normal. as I said would throttle 4800+rpm not in gear/neutral, only issue is when "in" gear moving.

Trim tabs up?

Was it getting on plane at 3,000? Were you taking heavy wind on the nose?
 
Tabs up and Down, Tried both. Yes could get on plane (barely) with tabs down some, no wind. I normally cruise at about 3300-3500RPM 25+/- MPH. Yesterday 21mph is all I could get. There was just no WOT yesterday
 
Bottom is clean, Full of fuel, 2 people, Nothing out of the normal. as I said would throttle 4800+rpm not in gear/neutral, only issue is when "in" gear moving.
Used to own this boat, WOT out of gear will not tell you anything.

Both engines suddenly will not hit WOT? That's odd IMHO. Original carbureted engines?
 
Used to own this boat, WOT out of gear will not tell you anything.

Both engines suddenly will not hit WOT? That's odd IMHO. Original carbureted engines?

Used to own this boat, WOT out of gear will not tell you anything.

Both engines suddenly will not hit WOT? That's odd IMHO. Original carbureted engines?


Yes, Original Carbs.
Yes Odd, I could see one or the other but not both at the same time. Will carb clean next weekend but I run Seafoam every 400 gallons for that purpose but, no guarantee.
 
Happiest day of my life when I moved to fuel injected - those carbs were picky.

I am not convinced it's engine related, unless it's bad fuel. Check your fuel water separators for water or just go ahead and replace them since you will have them off. That's the only thing both engines have in common.

Perhaps you dinged a prop, maybe it's the full fuel/water tanks, etc. I'd continue to test WOT as you burn thru fuel and use up water.
 
My 97 cruises at 30 mph at 3400 so sounds like something is up even before this issue. Maybe carb rebuild is needed but my guess is plugs or maybe plug wires.

I guess MPI might be better but my carbed engines work perfectly. I have not had to do anything to the carbs in the 12 years I owned the boat.
 
What an engine does in neutral is virtually useless, so forget about that part.

Are the engines pulling off one tank or individual tanks?

If one tank, a vent restriction is a possibility - try running with the fuel cap off. It would really odd for this to happen all of a sudden with both tanks.

Have you checked the fuel quality, yet? As noted above, just dump the F/W sep's into a clear, glass jar.

Morale of the story... there's something common here - focus on the parts of the system that are common to both engines.
 
My 97 cruises at 30 mph at 3400 so sounds like something is up even before this issue. Maybe carb rebuild is needed but my guess is plugs or maybe plug wires.

I guess MPI might be better but my carbed engines work perfectly. I have not had to do anything to the carbs in the 12 years I owned the boat.

Yeah, mine ran well for the most part, just love MPI, especially for a cold start. Once I got the "3 full pumps of the throttles then back to half throttle. stand on one leg, throw salt over my shoulder" to get them to start that is. :)
 
Yeah, mine ran well for the most part, just love MPI, especially for a cold start. Once I got the "3 full pumps of the throttles then back to half throttle. stand on one leg, throw salt over my shoulder" to get them to start that is. :)
That is a symptom of the Rochester Quadrajet well plugs on the carb. Its a poor design that after a few years, the plugs allow fuel to leak out of the bowl into the intake manifold. So when you have not run the boat for a week or so, you start with empty fuel bowls. That is why they crank for a while before they fire up, but not if you have run them in the prior couple of days. Its a minor annoyance, but they never fail to fire up once they get the fuel. There is a "fix" for it, but I have never bothered.

If I am going out fishing early in the AM, I usually go down to the boat the night before and fire them up, so in the morning its just a quick blip on the starters to get them fired up.
 

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