Noise and vibration

[mno555]

Hi All,
I Have a 73 F32 twin 302 fords.Absolutely love the boat. How do I fine out FOT rpms. I don’t push her past 3100 rpms. Also she seems to be very loud and I get a lot of vibration. She has always been this way. I have never run a ground and I check the props when pull her out in the winter. Does anyone know if this is normal? if not where do I start?
Thank in advance

[ready123]

Have you checked the alignment at the shaft coupler (in water)?
What kind of noise, exhaust or engine noises?
Do you have any insulation under the flooring inside engine room? I use metalized foam glued underside of floor for my soundproofing. Can talk in salon when underway, it is louder outside on the aft deck!
Solve vibration before you push to WOT..... Also look at engine mounts, are they sloppy?
Have you looked at engines and the shafts with floor open while running at 3100?
WOT = 4500 I believe.

[prowlersfish]

I belive at WOT the 2 barrel 320 should turn 4000-4200 rpm and the 4 barrell around 4200-4400 rpm at wide open , just going from memory .the only way to find out what you wide open rpm is to open her up . Then youll know if , You could be badly over proped and and that could be some of your noise and vibations issue . It would surely make other issues that Ready listed even worse .

What Hp 302s do you have ? Do you know what gear ratio you have and what size props ( diamater and pitch ) you have on the boat now ?

[mno555]

Thanks for the responses guys.
Have you checked the alignment at the shaft coupler (in water)? I am not sure what you mean. But I do have a slight wobble at one of the couplers. I believe its just engine noise. I don't have any insulation at all I was going to try that next. The engine mounts do look sloppy but don't get to much movement out of them. I would assume it would be like a motor mount in a car the engine would jump around ? No I have not looked at the engines at 3100rpms.I believe the engines are 225hp with 4 barrels and no clue what ratio and what props are on her. If I find out the ratio is there a formula or chart to follow to get the correct props. I was going to pull the props and shafts in the winter and have them gone over. But for all I know they could be the wrong props to begin with. And I wont push the WOT until issues are resolved over 3100 its not comfortable you fell that you might be damaging something. But I am no where near WOT so there are some issues for sure.

[aaronbocknek]

sloppy cutlass bearings can also cause vibration,or so i am told. engine alignment is done in the water because of the way the boat 'sits' in the water. any competent marine mechanic can do it. i had it done on my f-32 a year after i bought her and it turned out the port engine was out by only a 1/16th. once she was brought into 'true', at cruise, you could really tell the difference. it matters that much.

[mno555]

Over last winter I checked the cutlass bearings for any play didn't see any but didn't look them over that closely putting that on my winter list. I never heard of engine alignment I will look into that also. Thanks for the suggestions.