For the love of boating help lol

[mjm716]

Ok fellas I'm at my wits end, I have 30ft carver santego with twin Volvo penta AQ271C engines, 280 out drives, I'm gonna start from the beginning here. Port engine has been fine since beginning of June. Starboard side I rebuilt carb (Holley 4150) got it dialed right in, starts and idles and runs perfect even under load. So I think all is good, fill the gas tanks and all the sudden port engine will not go above 2500rpm with load on it, will rev in neutral perfectly. So I pulled the Holley and did a rebuild on it, put it back in dialed it in and starts on a dime and idles perfect, take it out put it under load and it's great up to 2500 rpm then it won't go any further, if I give more throttle the Rpms will drop. I have replaced the fuel filter also. Any ideas or direction would be greatly appreciated, my question is this a fuel delivery prob? Carb prob, I know that carb is good, it runs a lil rich at idle. Could it be a bad fuel pump, or pickup screen from running the tank low. If anyone has any tests or theory's I would love to hear them, I'm all out of ideas

 

[mjm716]

Bump

 

[PatinIdaho]

Start with a compression check.

 

[mjm716]

That was already done, engine has good compression

 

[PatinIdaho]

No Title

Next i would check timing. Base then total advance. I assume spark plugs/wires are all good and in proper order. If all that checks out then fuel problem i would guess.
I had one act like yours and turned out to be the timing advance was stuck. and broken springs.

 

[Scott Danforth]

Did you replace the power valve on the carb?

Run the port motor off a separate fuel source such as a 6 gallon portable tank

The stock prestolite dizzy is impossible to get parts for. Unlike the pic of the points dizzy that PatinIdaho posted, the 271C has a really expensive electronic trigger mechanism.

 

[Scott Danforth]

Is this a single tank carver, or do each motor have their own tank

 

[PatinIdaho]

The stock prestolite dizzy is impossible to get parts for. Unlike the pic of the points dizzy that PatinIdaho posted, the 271C has a really expensive electronic trigger mechanism.

Replaced mine with a Delco Voyager unit. MUCH better!

 

[Scott Danforth]

Replaced mine with a Malory. Have the old one in Craigslist

 

[mjm716]

Sorry guys I been at it for days with this engine, everything has progressively gotten worse and I am leaning towards a fuel prob, I replaced both fuel filters and rebuilt both carbs for a second time, motors are Barely running and still won't get over 2200 rpm on each of them. No power at all, I know I rebuilt the carbs correct, sadly I found lots of dirt/powder in the carbs, all over in there. Does anyone else think this is a fuel volume driver issue or fuel issue in general like bad gas???

 

[mjm716]

Keep in mind I can idle out of the marina, then when I drop the throttle to achieve plane it tops out at 2200 rpm with WOT

 

[PatinIdaho]

Did you just buy it or have you owned it a while?
These type of problems are hard to diagnose over the internet and a lot of answers are based off experience.
Im sticking with Timing not fully advancing.
By any chance do you have a Edelbrock 1409 you could bolt on and try?

 

[mjm716]

This is my first year with the boat, I have no extra carbs and timing has been checked with a timing light, boat ran fine then after fueling up it got progressively worse

 

[PatinIdaho]

Well maybe bad fuel or dirty lines carb?
Personally i would lose the Holley's and put 1409s on it. Holley's are a good carb for a race car but i never liked them much on a daily driver or a boat.
You can sell them on EBay and probably make almost enough to pay for the new 1409s Just my humble opinion.

Are they vacuum secondary's or mechanical and are they opening fully?

 

[mjm716]

They are vacuum secondaries, I'm afraid of switching carbs due to the linkage lining up

 

[PatinIdaho]

No Title

When i switched mine lined up perfect.

 

[dennis461]

Sorry guys I been at it for days with this engine, everything has progressively gotten worse and I am leaning towards a fuel prob, I replaced both fuel filters and rebuilt both carbs for a second time, motors are Barely running and still won't get over 2200 rpm on each of them. No power at all, I know I rebuilt the carbs correct, sadly I found lots of dirt/powder in the carbs, all over in there. Does anyone else think this is a fuel volume driver issue or fuel issue in general like bad gas???

Get out on the water, away from NO-WAKE zone.
Let engines idle for a bit, normally, the carbs would fill up full.
Then launch as hard as you can, watching tach.
If your boat takes off good and rpms come up without backfiring, then I would assume your distributers and carbs are OK.
( the bowls should hold enough fuel for this test)
If it then (within 30 seconds or more) dies out, it could be fuel delivery.

If you cannot launch hard, then look to dist advance and carbs.
Just because you rebuilt the carb twice does not mean you did it right :-(.

 

[mjm716]

I agree I could have done something wrong, but, it is a very simple carb and I have rebuilt it before with no issues, the only thing I question is which power cave to use in a Holley 4150, I put a 6.5 in which is stock in the rebuild kit, but it looks ever so slightly different than the one that came out