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50 liter high rpm issue not much power

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"Hi All. Having issues with WO

"Hi All. Having issues with WOT power. Here is the rundown. 1989 2150 with 5.0 liter, 4 bbl rochester

Had boat for 2 years, new outdrive last year with 1.30-1.94 gear ratio(don't know if this is correct)

Compression readings
1-135
2-145
3-135
4-145
5-145
6-145
7-135
8-145

New coil, New NGK plugs, Cap and Rotor new in 07
Plug wires new in 07

CHecked spark to all plugs, all great, shocked myself

Rebuilt carb 2 years ago, secondaries are opening up, fuel dumping in, checked fuel filter inline, ran with off still didn't fix it, took out the anti-siphon valve on top of tank, checked water separator

Here are all the prop readings

14.5 x 19 3 blade aluminum, 40 mph @ 3700 rpm
14.25 x 19 3 blade stainless, 37 mph @3700 rpm
14.5 x 18 4 blade aluminum, 37 mph @3900 rpm
14.25 x 17 3 blade aluminum, 35 mph @ 4000 rpm
14.25 x 16 4 blade aluminum 37 @ 4400 rpm

So now that you know all the details, here's the issue. Out of gear, boat rev's like a raped ape, no issues. WIth load, no real power out of hole and can't get to WOT which is 4200 - 4600. No real top end. Boat weighs 3700 pounds loaded, so no real issues with waterlogging I don't think, stored indoors every day for 2 years, never left in water. Trying to get to 45-50 mph at WOT of 4600. I know this boat can do that as I had one 15 years ago that ran like a kid from michael jackson. Please help before I throw motor away and get a 383. I am humble and will try anything.

thanks"
 
"keith r
Try this. Take a 1/8

"keith r
Try this. Take a 1/8" cotter key and straighten it out. Make a 90 degree bend on one end about 1/8" long so the metal looks like a "L"
Insert the bent end into the raised breather tube on the primary side of the carb. Fish around with the 1/8" bend and locate the top of the power piston lever and try and push it down gently. The lever should bounce up and down with moderate pressure. If it works this is fine, your power piston is operable. If it doesn't bounce try and hook it on the under side and lift it to free it up. Either way this plunger has to be active to move up and down to react to the vacuum fed to it. This piston controls two metering rods hidden inside the carb and will greatly vary your fuel feed through the carb.
Bert"
 
"As for the gear ratio, I am p

"As for the gear ratio, I am pretty sure this is just the sticker on the lower unit, not the gear ratio. Had lower unit changed 2 years ago. Probably going to take the top off and count gears to make sure."
 
Keith;
Are your secondaries &

Keith;
Are your secondaries (big ones at the back) opening up fully?
Maybe check with the spark arrestor off.
Is your choke butterfly open fully?
Is your base timing set correctly?
Any retrictions in your exhaust system?
Is the spark arrestor clean?

Your drive ratio should be 1.50
You can check this easily by turning the damper pulley nut CW with a socket and counting how many turns it takes to turn the prop one complete revolution in forward gear. That is much easier than pulling the drive top cover and you dont run the risk of twisting one of the cover bolts off.

Rod
 
"Ok. I will check the carb is

"Ok. I will check the carb issue and see if that is what is going on. As far as the Damper Pulley, you will have to help my ignorance. I will assume that is the one with the timing mark setup on it. Will it click along 20 or 22 times and let me know this or what? A mechanic said that one of the gears has 20 teeth and the other one has 22. is this right? Thanks for the help.

Keith"
 
"As far as the secondaries, th

"As far as the secondaries, they are opening up all the way, straight up and down. The choke butterfly opens about 1/2 to 3/4's of the way but even manipulating it with my finger, it still doesn't kick in all the way. Timing was set at 10 degrees btdc, and I have no clue on the exhaust system restriction. I think I will need to take the risers off and check the y pipe flappers to make sure they are there. Otherwise I don't know how to check the restriction. Exhaust blowing out of the prop with some force in idle so I don't think there is but I may be wrong.

Spark arrestor is spotless.

Keith"
 
"Exhaust flow at idle is about

"Exhaust flow at idle is about 1/15th of that at WOT, so what appears good at idle might not mean much. You may have lost an exhaust flapper, which will inevitably wind up caught in the Y pipe, half plugging things off.

Your choke should be wide open with the engine warmed up, within about 5 minutes of startup. If not, your choke heater is not working correctly.

Rod"
 
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