2001 50 hp merc

I have a 50 hp 2001 merc outboard motor on a 13 ft Paradise runabout.
Trouble is it has no real top end.. have tried several props and only way to get rpms up to 4900 is with 9 pitch prop and then speed is only about 18 mph.
with 14 pitch prop speed was only 27 at 4100 rpms.
Everyone that i have taken it to has said compression is VERY Good and all checks out good. But to me it seems as if something is limiting the engine,.
Boat is so small that the 50 hp should make it fly!!
Could some one have limited the top end on the motor or what is going on.
bought this from older man and he said that let grand kids putt around in it at Grand lake OK. I pulled flywheel off and eletrical part under fly wheel was not moving freely till i cleaned it up. Shop check it out after that and said that all was well but still no high end power... have been to 3 different Mechs!
HELP!
Thank you Dale Blankenship daleblank@sbcglobal.net

Re: 2001 50 hp merc

Do you have a long shaft motor on a 15" transom

Re: 2001 50 hp merc

No... that was one of the first things that was checked. Repair shop said that prop was correct Depth from bottom of boat and i have played with trim in various positisions and raised and lowered on Transom too.. Seems to work best where i have it now.. boat dosen't seem to have any top end and compression is like new. Motor dosen't seem to have much time on it as it seems almost new..
Thank you Dale

Re: 2001 50 hp merc

Dale, you might put a straight edge on the bottom of the boat the last 3' should be flat is your engine a 2 cycle or 4 cycle and is the bottom of the cavitation plate level or above the bottom of the boat 1 to 2 inches and parallel

Re: 2001 50 hp merc

Is this a bigfoot 50?

Re: 2001 50 hp merc

pwiseman said:

Is this a bigfoot 50?

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No standard 50 hp

Re: 2001 50 hp merc

Have you checked to see if the carb butterflies are opening all the way? With the air box off, open the throttle wide open. The butterflies should be perfectly horizontal in the carb bore. If not, link & sync is required. DO NOT adjust the throttle cable to make the carbs open further. That's not what that adjustment is for. Doing so would prevent the carbs from closing fully and idle speed would not be adjustable. Have you done a spark check to make sure you have good spark on all cylinders? You may have one cylinder not firing. I agree that a 13P prop should put that boat in the 30 MPH range or higher. And because it is a small boat, you might even be able to run a 14 or 15P. This is not a boat problem. A 9P prop would have overreved that engine severely so this is definitely an engine problem. Spark, fuel or compression is the culprit.

Re: 2001 50 hp merc

Laddies said:

Dale, you might put a straight edge on the bottom of the boat the last 3' should be flat is your engine a 2 cycle or 4 cycle and is the bottom of the cavitation plate level or above the bottom of the boat 1 to 2 inches and parallel

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2cycle
and Cavitation plate is aprox 3/4 to 1" above bottom at present time
we have tried it in 6 or 7 positions,, from 1 1/2 below to 2'' above.
i have even checked to see if foam filled safety comparments are water logged. (Never know,, seen that once before in Seattle.) they are not..
have moved fuel tank foreward aprox. mid hull.. just out of the way of my feet. helped it plane out little better as most of weight is in last 1/3 of boat.

Re: 2001 50 hp merc

Silvertip said:

Have you checked to see if the carb butterflies are opening all the way? With the air box off, open the throttle wide open. The butterflies should be perfectly horizontal in the carb bore. If not, link & sync is required. DO NOT adjust the throttle cable to make the carbs open further. That's not what that adjustment is for. Doing so would prevent the carbs from closing fully and idle speed would not be adjustable. Have you done a spark check to make sure you have good spark on all cylinders? You may have one cylinder not firing. I agree that a 13P prop should put that boat in the 30 MPH range or higher. And because it is a small boat, you might even be able to run a 14 or 15P. This is not a boat problem. A 9P prop would have overreved that engine severely so this is definitely an engine problem. Spark, fuel or compression is the culprit.

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Will check Carb butterflies tomorrow. Had not thought of that!
Would shop have checked that??

Jimmy Houston Marine checked the spark last summer and rigging
all was well and even checked if all componets were correct for this motor.
will check fireing again tomorrow too.. has new plugs installed.
motor runs smooth no hesatation(sp) no miss

boat came with 4 blade but could go only 2800 rpms don't know pitch.
i replaced it first thing when i bought boat.

thanks again Dale

Re: 2001 50 hp merc

daleblank said:

Will check Carb butterflies tomorrow. Had not thought of that!
Would shop have checked that??

Jimmy Houston Marine checked the spark last summer and rigging
all was well and even checked if all componets were correct for this motor.
will check fireing again tomorrow too.. has new plugs installed.
motor runs smooth no hesatation(sp) no miss

boat came with 4 blade but could go only 2800 rpms don't know pitch.
i replaced it first thing when i bought boat.

thanks again Dale

Click to expand...

checked the Carb butterflies and all opned fully.
Pulled spark plugs again and top plug did not seemed to be as burnt/used as lower 2 so i installed 3 new plugs. re checked all plug wires and put earmuffs on motor and ran the motor for a couple mins. all 3 plugs seemed to be firing as all 3 appeared to feel like same temp aat 30 Sec,, 60 sec and 90 sec..... While i was pumping fuel to carbs to start motor,, i noticed that prime bulb in fuel line was leaking and might be sucking air.
got new one tonight and i am going to install it tomorrow. to see if any changes. will post results tomorrow pm.
Thank you Dale B