Shake, rattle and roll

[Esgbradford]

Hi there. Quick introduction first. I'm Eric, I bought a 1975 Newport 27 in February. The atomic four wasn't working (in fact, the previous owner used an outboard). I replaced the basics, etc, and got the engine running.

But she runs very rough. Ummm... that's not quite accurate. The whole boat vibrates and rattles very annoyingly when running much more than a idle. Perhaps "very annoyingly" is a bit of an understatement...

The boat does not rattle at idle, at idle in gear (FWD or REV), or at perhaps idle plus 10% in gear.

Anyone know what I should check? broken propeller, bent drive shaft, what have you?

Thanks in advance for your help.

Eric
Aries Newport 27
Portland, OR

[CalebD]

I'm no expert.

Eric,
I would have to guess that your engine alignment is out of true and the noise you hear is a result of the shaft shaking or vibrating.
One item you must check is the engines mounting bolts. If they are loose then the engine can move around a little bit, enough to cause alignment issues.
I would also guess that your Cutlass bearing and/or stuffing box are taking some end of the wobble as well which may actually be causing the vibrations. If the shaft is not true you can expect to hear and feel more vibrations from your engine and it is not good for any of the linkages.
You will figure it out. Asking questions is a good start.
If there is no noise in neutral but a lot of noise when in fwd or rev then it is most likely the shaft alignment.

Congrats on getting your A4 to turn over and welcome to the home of the Afourians.

[jpian0923]

I would recheck timing and distributor wires. You mentioned in another post "I set the timing -- I imagine that since the previous owner had the wires rotated 90 degrees on the distributor that this was the cause of him not using the tank."

Firing order is 1-2-4-3.

On most distributors, in this forum, plug wire #1 is positioned at 9 o'clock (if looking at top view of distributor.) Then, clockwise from there is, #2 then #4 then #3.

Rotor position for #1 cylinder should be pointing at 9 o'clock when piston #1 is at top dead center.

[Dave Neptune]

Prop?

Eric, could be as simple as folding prop not unfolding. Check the shaft while the engine is idling in gear, if it is rockin you found it.
Also it could be the tune of the engine is not up to shuff, ie timing , firing order or just plain missing on a couple.

Dave Neptune

[Esgbradford]

I would recheck timing and distributor wires. You mentioned in another post "I set the timing -- I imagine that since the previous owner had the wires rotated 90 degrees on the distributor that this was the cause of him not using the tank."

Firing order is 1-2-4-3.

On most distributors, in this forum, plug wire #1 is positioned at 9 o'clock (if looking at top view of distributor.) Then, clockwise from there is, #2 then #4 then #3.

Rotor position for #1 cylinder should be pointing at 9 o'clock when piston #1 is at top dead center.

Yes. That is how I found it. But I did the trick of putting my thumb on piston 1 spark plug hole, and then having someone turn the crank until I felt the pressure that I could not hold back with my thumb. I looked at the rotor and it was between 5:00 and 6:00. So, I conclude that piston #1 on my engine is at 6:00. It runs there. It doesn't run if wired for piston #1 at 9:00.

I can send video or pics if that'd help illustrate.

Eric

[Esgbradford]

Eric, could be as simple as folding prop not unfolding. Check the shaft while the engine is idling in gear, if it is rockin you found it.
Also it could be the tune of the engine is not up to shuff, ie timing , firing order or just plain missing on a couple.

Dave Neptune

Folding prop? Ooo, that'd be cool. I just assumed the prop was fixed, never though it might have a folding prop.

[JOHN COOKSON]

Different boats have different engine installations and access.
#1 position on the distributor will be at 12,3,6,or9 depending on where your head is when you view the distributor.
It's my understanding from the forum that there are fewer belt clearance issues if #1 position is furthest from the engine.

TRUE GRIT

[jpian0923]

It may work the way you have it but...

This may help. http://www.moyermarine.com/faq/4.8.html

We love video around here. Post to youtube, paste the url in a message here.

[ILikeRust]

Yes. That is how I found it. But I did the trick of putting my thumb on piston 1 spark plug hole, and then having someone turn the crank until I felt the pressure that I could not hold back with my thumb. I looked at the rotor and it was between 5:00 and 6:00. So, I conclude that piston #1 on my engine is at 6:00. It runs there. It doesn't run if wired for piston #1 at 9:00.

This is entirely possible if someone pulled the distributor out at some point and re-inserted it with the rotor pointing 90 degrees away from the recommended position.

[jpian0923]

For my distributor the recommendation is for it (rotor) to point directly starboard (9 O'clock).

[sastanley]

Jim, is that looking at the distributor from the flywheel end or the reversing gear end? It is all a matter of perspective. For those of us with top-down engine access the orientation may be different than folks with an engine, say under the stairs, and they only look at it backwards all the time.

I always try to look at it from the perspective of the flywheel end of the motor & boat direction being 12 o'clock. In my case, the rotor points to stbd away from the engine at #1 TDC which I'd call the 3 o'clock position. - Now, if you are weird like Ed C & have the engine put in backwards, that is another can of worms. (V-drive)

This is where pictures are valuable because we can draw on them (literally) and get everyone's perspective on the same page.

I'd make sure the prop is clean first...the entire boat will shudder if only blade of a folding prop opens. After I confirm a clean prop, then I'd start over again from scratch with the timing to make sure it is right. In reality it can be anywhere you want as John noted, but it is easier to troubleshoot in the future if you go with the herd.

[jpian0923]

I should have been more specific, I apologize.

I have a direct drive and I'm viewing it from fly wheel end.

I was on the boat last night, should have taken a dang picture.

ALso, I thought it would be easier to redo timing rather than get in the water to check prop. But that's because the water here is cold.

[sastanley]

All good Jim...just trying to avoid confusion.

I am hoping the hurricanes have swept out the sea nettles here in the Chesapeake, so I can do one last swim (water is colder than normal due to extreme rains from the storms, about 70F) to get the prop clean one last time for fall sailing.

I am going to need to haul the boat in the spring regardless...I have chunks of bottom paint missing & didn't haul this year at all (just cleaned by diving) - I really need to sand off 30+ years worth of paint and start over...not much growth here over the winter though.