4000 rpms????

[88 regal 3.slow]

hello all i also have this posted in the prop forum... i have a 19 ft 1988 regal sebring w a mercruiser 140 i/o 14.5x17 prop... the boat is only reving at WOT 4050 rpms!!!... i just did a complete tune up ..plugs wires,cap, rotor, condensor,points,coil, and fuel filter, points set a .022...i know the boat shoul drev near 4600 at WOT but im no where close please help...ohh and i also set the timing to 6deg BTDC.which drasticaly improved starting...

 

[MikDee]

Re: 4000 rpms????

Make sure your mecanical advance is working in the distributer, the rotor should turn forward a little with spring pressure pulling it back, one direction or the other. Also, make sure your throttle is opening fully with the control handle.

 

[88 regal 3.slow]

Re: 4000 rpms????

so your saying pull the cap off and try to slide thr rotor foward and backward???? what if it doesnt move?? it is brand new....

 

[88 regal 3.slow]

Re: 4000 rpms????

bump....

 

[MikDee]

Re: 4000 rpms????

On that motor, I don't believe you have electronic advance (computer controlled) I do believe that if you grab the rotor shaft, it should rotate a little one way, or the other, and spring back by itself when you let go. Or your not getting any mechanical spark advance, it's corroded frozen under the breaker plate, get out the liquid wrench, and spray it, then work it till it's free.

 

[88 regal 3.slow]

Re: 4000 rpms????

im a little confused on exactly what to do .... pull off the rotor and twist it ??

 

[Coors]

Re: 4000 rpms????

I don't know your engine, as I have an OMC (crowd boo's), but you need to set the points with a dwell meter, then set the timing per the manual.

 

[ziggy]

Re: 4000 rpms????

List of possible causes of low WOT.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation (Full tuneup done recently)
• Remote control cables and linkage for proper travel to open throttle plates fully.

__________________

by don s

I have an OMC (crowd boo's)

i'm sorry coors, thats funny......personaly, i'm happy for anyone that's one the water in any kinda boat.......

im a little confused on exactly what to do .... pull off the rotor and twist it ??

if ya got mech. weights, which i don't know one way or the other........leave the rotor on. that'll give ya something to twist on.....

 

[QC]

Re: 4000 rpms????

Have you ever seen more than 4050 with that exact boat, prop, engine before?

 

[Don S]

Re: 4000 rpms????

I'm with QC, has it ever been at 4600 rpm?????

You aren't running with the drive ALL the way down are you? If so, you need to trim it up for best rpm/speed.

 

[88 regal 3.slow]

Re: 4000 rpms????

i have had the boat 2 seasons and yes i did see 4300 out of it when i had a diff size prop on it 13.75x17 but the boat wouldnt move at all ... the nose went up and thats it... like it wasnt pushing enough water.... the points are set to .022 and timing is at 6 BTDC.... And yes thats with the drive trimmed up with the drive down im lucky to pull 3800 out of it...

 

[QC]

Re: 4000 rpms????

OK . . is the bottom clean? How about waterlogged flotation? Waterlogged or not, you need to try a 15 inch pitch. I am confused about one other thing too . . . How did you get 4300 out of the other prop if the boat "wouldn't move"? Doesn't seem right. Do you still have that other prop? Try trimming in (down) to get her on plane and then trimming out (up) . . . Also, if you can't get the bow up at WOT then try moving some weight aft. This can also help with speed which will help with your WOT RPM as well. I am starting to think this only a prop issue though. An older 19 footer, that has gained some weight over the years, may only be able to pull 15" . . .

 

[Coors]

Re: 4000 rpms????

I was wondering that "bow up, not moving" too.
My stepson was saying that with my boat, went out and watched him run and trim.
Cavitation.

 

[88 regal 3.slow]

Re: 4000 rpms????

yea i dont understand either i put the 13.75 17 on it and the boat was screaming but not moving anwhere at all.....i didnt put the prop on by choice i was reccomended that size by a local retailer.... when i brought the prop back to him and complained he claimed the prop i was sold was a size for a outboard motor... props confuse me in general lol ..... so i went back with the same size prop that i had last season and the boat gets up on plane.. but just doesnt pull any rpms... what would a 15 do ???? (or what is it supposed to do rather ....in comparison to my current setup) thanks guys for all the replies i really wann figure this one out....

 

[MikDee]

Re: 4000 rpms????

Ok, Back to the timing advance, (read my lips,,,lol) inside the distributor is the points, condenser & rotor, with the motor off, try grabbing the rotor while it's on the distributor, and see if it rotates clockwise, or counterclockwise, with some spring pressure pulling it back in place,,, If it doesn't move, that is a major problem, you're timing advance under the breaker plate is not working! take off the breaker plate, and lube it to free up the weights, & springs. On some engines the weights, & springs are under the rotor itself.

 

[BRG25]

Re: 4000 rpms????

I suppose you checked to make sure your Tach is accurate?

 

[88 regal 3.slow]

Re: 4000 rpms????

ok im going to do that right now i read ur lips lol hopefully that is the problem il get back to you hope you not sick of this thread yet lol....

 

[Haut Medoc]

Re: 4000 rpms????

I doubt you would get 4000 out of it if the advance weights were stuck.....
The only way to knowfor sure is to put a timing light with advance on it......
Have you ever tested the compression?.....​

 

[paulrfrancisco]

Re: 4000 rpms????

so your saying pull the cap off and try to slide thr rotor foward and backward???? what if it doesnt move?? it is brand new....

I think some of you missed this... he said the distributor is new,,,

Also...

with the motor off, try grabbing the rotor while it's on the distributor,....

It would be pretty odd if the you could grab the rotor and the engine was running....not sure how one could do that...

 

[Haut Medoc]

Re: 4000 rpms????

I think some of you missed this... he said the distributor is new,,,

Also...



It would be pretty odd if the you could grab the rotor and the engine was running....not sure how one could do that...

Very quickly, would be my guess!......