MOTOR VIBRATION

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akblackdawg
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MOTOR VIBRATION

Post by akblackdawg »

Ran my new boat for the first time today and it has a bad vibration. When Skip ran it without the prop, he said the vibration was there then also, so eliminate the prop. Looking close at the hormonic balancer. Has a pro comp balancer, it is fluid filled. Don't see anything that looks like a weight could have come off it, I plan on pulling it tomorrow. For those who don't recall, I'm not a great mechanic so don't get too technical on me, spell it out in baby talk :lol: . Looking at the flex plate, the weight is still on it and it looks good from below. Do balancers wear out or become damaged, possible damage in shipping, motor had 100 hrs on it and shipped by truck on skid. Dist cap arrived broken so something happened. I trust the seller that the motor was running smooth when shipped. will check the key way and for any sign of problem with the nylon ring built into the balancer. Any other ideas, Bud

I surpose I should take a look at the timing tomorrow before pulling it, if timing shows way off it might indicate the balancer spun.
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John Fenner
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Re: MOTOR VIBRATION

Post by John Fenner »

Just double check that the harmonic dampener has a counterweight for the external balance, I seriously doubt that shipping could induce a vibration if only the dizzy cap was busted.
Yes,, check timing and double check firing order as you changed dizzy cap,5 and 7 are easy to cross. Go to the simple things first!
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Re: MOTOR VIBRATION

Post by Ruagatr »

John is dead on. Motor missing can cause vibration and all of us have checked the plug wires ten times and something changed on the 11th time. Lol. So run the firing order down for each wire. If timi g good then pull each plug one at a time and see if there is one that is strangely different than the rest. Report back to us and we can follow through.

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Re: MOTOR VIBRATION

Post by HOLOTYPE »

Check for vacuum leaks while you are at it.
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air-roberts
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Re: MOTOR VIBRATION

Post by air-roberts »

well what size motor is it first?
and internally or externally balanced?
and it you have a fluid dampener they can not slip.
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emmitt Kelly
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Re: MOTOR VIBRATION

Post by emmitt Kelly »

I also want to know what the vibration cause is...my engine is stock BBC from Marine Power...I have the same prop

I noticed you have a different brand of reduction...

I have to put my overcoat on when watching Ice Pilots!!!

your weather up there is the supreme test......almost like Buffalo airways in their c46 and 47's

keep us posted...
Last edited by emmitt Kelly on Fri May 18, 2012 9:32 am, edited 1 time in total.
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Re: MOTOR VIBRATION

Post by flying fish »

Like John and Ruagatr suggest. Keep it simple.

Process of elimination. Quite probable a dead or weak hole causing your problem.
Plugs are cheap. I would change the spark plugs and the rotor before I started trouble shooting.

If you still have a vibration after changing plugs and rotor, bring engine up to vibration RPM. Then, it is easy to use a test light grounding each each individual spark plug wire, one at a time, again, at the vibration RPM and see which hole is the culprit.

When grounding one plug wire at the sparkplug boot, the engine should change how she sounds. If you find grounding one exact plug wire doesn't change how engine runs, you found your culprit cylinder.

Don't think to far outside the box. Should be easy fix. No worries Bud-

* Use a test light with a sharp pointed end and poke this sharp end into the plug wire boot accessing the crimped metal end that slips over the spark plug. Clamp the ground end of the test light to a head bolt or whatever you choose to get a good ground.

You can also remove spark plug wire (one at a time) and do the same test, but for me, I am a wuss and don't want to get shocked. I am scared of this shocking thing, so I use a test light as described. :)

Almost forgot- Ask engine builder if he has installed a camshaft with a 4/7 swap on firing order.
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akblackdawg
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Re: MOTOR VIBRATION

Post by akblackdawg »

I did a few things today, no improvement. One thing I didn't mention yesterday, the vibration was so sevear that the rt rear motor mount snapped, so I replaced it today. the radiator also shook loose, had to remount it, glad it wasn't distroyed, new, cost me 250+300 air freight, had 4 screws across top and 4 across bottom, most of top screws just rattled loose and i replaced, bottom ones pretty well distroyed most of the flange and I put in new screws on the remaining flange. gotta get this fixed before I go out again for sure. i double checked spark plug wires, they are all correct, timing was way way advanced, so I set it back to 30* at 3000 rpm. checked each header pipe and all cylinders were hot. will do more tomorrow, pull plugs, check compression if I can find my compression gage :). will go down the list you guys gave me. I'm thinking when dist cap was broken in transit, may have moved dist to further advance. thank you, Bud

Air-Roberts, the motor is the same 489 bbc as shown below, externally balanced

FF, no 4/7 swap on the firing order
Last edited by akblackdawg on Sat May 19, 2012 2:03 am, edited 1 time in total.
:alaska: If you ain't living on the edge, you're taking up to much space.

15x8 Alumatech hull, with enclosed cab, aluminum cage, LS 3, 6.2 aluminum block ffi, 2.7 Balistic Box, sensinich superwide 3 blade. Built for year around riding in Alaska

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John Fenner
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Re: MOTOR VIBRATION

Post by John Fenner »

I will be waiting with a bucket of popcorn and cold cold beer!
I never finish anyth,,,.

rockyd
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Re: MOTOR VIBRATION

Post by rockyd »

I had the same problem with my 383 stroker. Changed spark plugs, and that fixed the problem.

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emmitt Kelly
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Re: MOTOR VIBRATION

Post by emmitt Kelly »

I am not an expert..but...if you broke a mount bolt..something is way off more than a dead cylinder to cause that much imbalance.

question, have you checked the torque on your prop hubs? is there sealant around the base of the prop at the hub?
has it rained on your airboat while boat is uncovered possibly letting water into the hub?

the mechanic that installed gearbox...did he put slippage marks on all the bolts? if so are any lines misaligned?

I would turn the engine and look for loose or missing bolts on the flywheel/flexplate or cracks.

keep an eye on your radiator developing a stress crack and start leaking and overheat your new engine.

I am a worry wart...have been all my life...can't help it...sorry

that is "borderline" dangerous when the force is so powerful it will snap mount bolts.

Be safe up there..
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Re: MOTOR VIBRATION

Post by cntry141iq »

You need to find the problem .. you have too much money invested to destroy it. you do not need to take it out to see what happens ... unless you want to see some catastrophic damage. I am not being a butt head .. just either find the problem on your own with the advice given or else take it to some one who can ... you are lucky you didnt destroy your new boat.
Don't waste your time ... it is the only thing you can't get more of
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Re: MOTOR VIBRATION

Post by skip olsen »

If I Was You Bud I Would Support The Back Of The Engine Like I Was Telling You And Pull The Reduction Off And Start The Engine That Way You Will Know Its Not The Reduction Unit But Not Only That You Will Be Able To See The Flex Plate And Make Sure Its Not Cracked Our Broke. It Should Have A jw Wheel On It Any Way, Not That Stock Flex Plate. And If That Does Not Stop The Vibration I Would Pull The Motor Out And Pull It Apart And Find Out What The Problem Was. Guys I Checked Every Thing You Asked Bud To Check. Its Ether The Reduction Unit Our There Is Some Wrong Parts On It Some Where. When I Build Motors Up Here There Balanced This Has A Bad Balance Problem Some Where. I Hate To See Bud Run It Much Because It Could Cause Internal Problems Like Take A Bearing Out. Bud Picked It Up Before We Could Take It And Run It And Check It Out And Figure Out What Was Going On.

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Re: MOTOR VIBRATION

Post by Gonzo »

The harmonic balancer and flywheel are different on externally balanced 454 family. 396,402,427 are internally balanced. If you do not have correct front and rear- Yes it will buzz. Crate motor? I think I would pull prop / box and confirm both P/N and physical look for counter weights on flywheel and balancer. I would also pull oil filter and cut open and make sure you have not started knocking bearings out. The more you run it- the greater chance of shotening life, shaken motor syndrome is never a good thing. Gonzo

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Re: MOTOR VIBRATION

Post by dantheairboatman »

how much does the tip of the prop move in relation to the balancer? this will tell the tell in the flex plate.
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JAMES
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Re: MOTOR VIBRATION

Post by JAMES »

akblackdawg wrote:Ran my new boat for the first time today and it has a bad vibration. When Skip ran it without the prop, he said the vibration was there then also, so eliminate the prop. Looking close at the hormonic balancer. Has a pro comp balancer, it is fluid filled. Don't see anything that looks like a weight could have come off it, I plan on pulling it tomorrow. For those who don't recall, I'm not a great mechanic so don't get too technical on me, spell it out in baby talk :lol: . Looking at the flex plate, the weight is still on it and it looks good from below. Do balancers wear out or become damaged, possible damage in shipping, motor had 100 hrs on it and shipped by truck on skid. Dist cap arrived broken so something happened. I trust the seller that the motor was running smooth when shipped. will check the key way and for any sign of problem with the nylon ring built into the balancer. Any other ideas, Bud

I surpose I should take a look at the timing tomorrow before pulling it, if timing shows way off it might indicate the balancer spun.
who did u buy that motor from a ind. or comp. ? i assume since it was shipped used u never head it ran .. :shock:
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Re: MOTOR VIBRATION

Post by :) »

Post a pic of ur motor stand. Mines got a vibration too but only at idle. I found that mine was in the stand.. I have one of the weirdest engine stands I've seen.
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Re: MOTOR VIBRATION

Post by flying fish »

skip olsen wrote:If I Was You Bud I Would Support The Back Of The Engine Like I Was Telling You And Pull The Reduction Off And Start The Engine That Way You Will Know Its Not The Reduction Unit But Not Only That You Will Be Able To See The Flex Plate And Make Sure Its Not Cracked Our Broke. It Should Have A jw Wheel On It Any Way, Not That Stock Flex Plate. And If That Does Not Stop The Vibration I Would Pull The Motor Out And Pull It Apart And Find Out What The Problem Was. Guys I Checked Every Thing You Asked Bud To Check. Its Ether The Reduction Unit Our There Is Some Wrong Parts On It Some Where. When I Build Motors Up Here There Balanced This Has A Bad Balance Problem Some Where. I Hate To See Bud Run It Much Because It Could Cause Internal Problems Like Take A Bearing Out. Bud Picked It Up Before We Could Take It And Run It And Check It Out And Figure Out What Was Going On.
Bud-
May want to think about taking the boat back to Mr. Skip. Sorry man, but the boat was in an experts hands, and he did not get to finish. Remember, an expert in Skip.

A dead hole will not cause the kind of vibration you mention. IMO-Whether it be a fouled plug, an out of adjustment valve, or a flat cam lobe, none of these things will cause the kind of vibration you mention. It seems not good judgement to run your new ride long enough to cause the self inflicted damage you describe. If you haven't already, you will wipe out the bearings in your engine.

Take her back to Mr. Skip!!
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Re: MOTOR VIBRATION

Post by JAMES »

flying fish wrote:
skip olsen wrote:If I Was You Bud I Would Support The Back Of The Engine Like I Was Telling You And Pull The Reduction Off And Start The Engine That Way You Will Know Its Not The Reduction Unit But Not Only That You Will Be Able To See The Flex Plate And Make Sure Its Not Cracked Our Broke. It Should Have A jw Wheel On It Any Way, Not That Stock Flex Plate. And If That Does Not Stop The Vibration I Would Pull The Motor Out And Pull It Apart And Find Out What The Problem Was. Guys I Checked Every Thing You Asked Bud To Check. Its Ether The Reduction Unit Our There Is Some Wrong Parts On It Some Where. When I Build Motors Up Here There Balanced This Has A Bad Balance Problem Some Where. I Hate To See Bud Run It Much Because It Could Cause Internal Problems Like Take A Bearing Out. Bud Picked It Up Before We Could Take It And Run It And Check It Out And Figure Out What Was Going On.
Bud-
May want to think about taking the boat back to Mr. Skip. Sorry man, but the boat was in an experts hands, and he did not get to finish. Remember, an expert in Skip.

A dead hole will not cause the kind of vibration you mention. IMO-Whether it be a fouled plug, an out of adjustment valve, or a flat cam lobe, none of these things will cause the kind of vibration you mention. It seems not good judgement to run your new ride long enough to cause the self inflicted damage you describe. If you haven't already, you will wipe out the bearings in your engine.

Take her back to Mr. Skip!!
You trusted Skip to build you a boat. Let Skip finish his masterpiece.
i agree
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Re: MOTOR VIBRATION

Post by Norris »

In one of your posts you say it is externally balanced, that would mean your harmonic balancer has a weight either machined into it or bolted into it. It would also mean the flex plate has a weight welded on to it. You have to install or time the flex plate to the crank. Both the crank and the flex plate have a hole for a dowel, but sometimes the dowel is missing from the crank and folks bolt the flex plate on in the wrong clock position.

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Wild Bill
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Re: MOTOR VIBRATION

Post by Wild Bill »

Not sure what they did however it ran fine before I shipped it...
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Prop off to Sensenitch for re-balance
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Re: MOTOR VIBRATION

Post by akblackdawg »

The motor came complete with prop hub to hormonic balancer in one unit. Bill sent me a vidio of the motor running the day it was packed for shipping. There was not a problem when it was shipped. Skip says it arrived with a broken dist cap, damaged in shipping. So there may be more damage to the distributor then we fixed just by putting on new cap. Bill told me it had a couple rockers with bad nuts on them, I ordered new rockers with nuts and skip changed out a couple nuts and adjusted them. Skip ran the motor on the stand and said it had a little vibration issue. it did vibrate at idle and i ran it the other day, vibration got much worse half way though the ride and i headed back, i'm guessing that is when the motor mount snapped. Sorry to say, the motor is runing much rougher now then before the ride.

I DO NOT BLAME OR HOLD FAULT IN ANY WAY TOWARDS SKIP OR BILL. SKIP BUILT THE BOAT AND INSTALLED THE MOTOR, HE HAD NOTHING TO DO WITH THE CONDITION OF THE MOTOR. BILL SOLD ME THE MOTOR IN GOOD FAITH AND I AM CONFIDENT THE MOTOR WAS RUNNING GREAT WHEN SHIPPED. Yes, if i don't find a problem quick, i will take it to a mechanic who knows what they are doing. i was late picking up the motor due to some other obligations and skip was leaving the next day for florida and that is why we didn't take the boat out. that was my decision. Skip is not responsible for the motor, that is mine. Norris says there should be external weight on the balancer, I don't see one at all. Nothing on the front except the pully. As best as I can see, nothing on the back. I will pick up a puller today and pull the balancer. Also, to mention again, the timing was way way advanced, off the scale, and i set it back to 30* at 3000 rpm. Thanks for the concern. Bud
:alaska: If you ain't living on the edge, you're taking up to much space.

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Re: MOTOR VIBRATION

Post by chuckitt@earthlink.net »

Check the float levels in the carb. If the level is low, it will run lean and cause the motor to shake. I see a 1 inch spacer under the carb which adds to the size of the plenum which will also make it run lean and may have to go up about 2 jet sizes. If most of the shake is from idle to about 1500 rpm, install a 50 cc pump kit on the primaries and drill the squirter out to .037.. Install the pump cam ( brown ) upside down to get a hard shot. This should make the boat get on plane quick.
Also when riding, if the fuel pump is not big enough to keep the fuel bowls at the right float level, it will go lean and the engine will shake and the prop is hooked to the shaking engine so it will make it shake more.
So check out the complete fuel system before going into the engine.
Thanks, Chuck

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Re: MOTOR VIBRATION

Post by pipedog »

Man that sucks, I hope it's something minor!! Good luck Bud.
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Re: MOTOR VIBRATION

Post by akblackdawg »

I removed and replaced the balancer today. It appeared fine, weight in place on back of it no problem. Had a Professional Products balancer on it, numbers are right for the bbc. Primary reason I did it now was because Skip had thought it seemed to him like that might be it. I really examined the flywheel closely and felt up to the hub all around and it seems fine, has no wobble when running. Yes, when putting on the prop skip used a lubricant of some sort to seat them in the hub, had to wipe the excess off the hubs after running. Maybe I'll pull the distributor and make sure it isn't bent or something, since the cap had been broken in shipping.The carb information is interesting except I know nothing about carbs. The pic shows the spacer but it had run good for 100 hrs with that spacer, Skip did remove it and put on a water heated spacer about the same thickness, we run those up here to keep the carb from icing up in winter. Need to pull the filter and tear into it also, looking for metal. Bud

Actually my mistake, timing was way retarded when I ran it, now at 30 but is rougher then it was before.
:alaska: If you ain't living on the edge, you're taking up to much space.

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