Engine Vibration - Maxum Boat Owners Club

Diggman33 · 06-23-2008, 05:32 PM

Greetings fellow Maxum owners!

This is my first post! What a great discovery finding this website!! Here's my situation... I recently purchased a 1994 2000 SC, 3.0 LX w/Alpha 1 outdrive and (sadly) Im experiencing an excessive engine vibration issue. It is only noticable at idle to ~1100 RPM, but it is so excessive the entire boat shakes violently whether the drive is engaged or not.
So now my questions... Has anyone experienced this problem? What was the cause/source of the problem? How much did it cost to fix the problem? Should I hold off from using the boat until the vibration problem is fixed?

Thanks for your help!

Fair winds and following seas -

seapuppy · 06-23-2008, 06:00 PM

well...the very first thing is welcome to the zoo...hope you can stick around some...

second...when was the last tune up done on it...being a 3.o ltr engine...it's gonna vibrate some....but if the spark is falling off at idle ..then yeah...it's gonna shake like an out of balance blender.......new plugs...rotor...distr. cap....and wires!!!....will probably fix it....atleast this is the cheapest avenue to persue ....then if it's still doing it...there are other things that need to be asked....

SP

Diggman33 · 06-23-2008, 07:14 PM

Hi SP, Thanks for the welcome and your response. The plugs, cap, rotor, wires, fuel filter, oil, etc were done the end of May. The boat has been used twice since then. I suppose I could shoot a timing light on it to see if there's a timing issue, but I am curious what the next level of questions to ask are...
Thanks!
Steve

seapuppy · 06-23-2008, 08:03 PM

well..the 4 bangers are notoriously nervous.....so....one thing to check out is if there is a vacuum leak at the carb....get a squirt bottle of soapy water and spray at the base of the carb while it's idling.......if it smooths out...retorque the carb down....you might also try adjusting the idle mixture screws....run them in until seated lightly..then back out 1.5 turns...back out .5 turns at a time until it smooths out...then stop.....adjust idle to 650-700 rpms....if that doesn't do it...you got something else going on...maybe a bad plug wire or dead plug at idle....

SP

Diggman33 · 06-24-2008, 05:29 PM

So this morning I did a compression check on all 4 cylinders, thinking (but not hoping) that I might find a bad cylinder. Readings are #1 @ 132, #2 @ 120, #3 @ 135 and #4 @ 122... for the most part acceptable (within 20psi). I did make the following observation... the engine shakes wildly when I was cranking it... the bucking with transmitted throughout the entire boat, and the stern looked like it was about to snap off. So I assume that it's not a carburator or ignition issue, but rather something is either misaligned or loose... or even worse, maybe the crank is out of balance?
Any thoughts would be greatly appreicated!

seapuppy · 06-24-2008, 06:46 PM

man...if your doing that much movement...something is definitely off...I'd check back of the engine but also ...make sure the firing order is correct.....that may be the problem........in the back the only thing that could cause that much movement is the u-joint or copler.....check those...other than that ..no way the crank can get out of balance....you'd hear something rattling around down there...

SP

Gazjen · 06-24-2008, 07:17 PM

Are these engine externally balanced? if so has the front pulley come loose from the crank, well not the pulley the balancer behind it

Or could be fly wheel loose or drive plate

Gazjen · 06-24-2008, 07:21 PM

Just re read your post has it done it from day one of owning the boat?

Or is it something that's just started?

Diggman33 · 06-24-2008, 10:05 PM

I noticed the engine shake when I went to look at the boat the first time (it was on the trailer). The boat had just been tuned and readied for summer so I asked the previous owner if the marina had pointed out the engine shake, but apparently they didn't. I also called the marina and spoke to the service department and they didn't have anything noted about it in their service logs either. Everything looks mint under the hood, and it runs like a champ at speed... oil pressure, temp, everything is within spec.... just shakes like the engines sitting on jello when your at idle.
Im going to bring it in for an appointment to the marina that worked on it last - they've serviced it for the last 3 seasons so hopefully they can figure out whats going on.

seapuppy · 06-24-2008, 10:29 PM

I just drove a 3.0ltr engine about a month ago...it didn't shake like your describing.......somethings off then....let us know what is going on....

SP

Gazjen · 06-25-2008, 09:05 AM

My moneys still on the balancer or flywheel etc

I've had 4 cylinder engines running on two before and they didn't vibrate they just sounded bad

Diggman33 · 06-25-2008, 07:20 PM

Just dropped her off at the Marina. I'll let you guys know how I make out. Hopefully something simple (and easy to fix)... but when is that ever the case!

Diggman33 · 06-26-2008, 10:21 PM

The word from the service department is that the choke was stuck, and that was causing the engine to run rough at idle... thus causing the engine to shake like it did. They adusted it, ran it up... reinspected, and took care of the shake. They tested it again later in the day, and it was running ugly again... on and off... so they think the carb needs to be rebuilt. Any thoughts on a rebuild, or should I look into getting a fresh new carb?
Thanks!
Steve

seapuppy · 06-26-2008, 11:02 PM

have them replace the choke....a rebuild isn't necessary when it's just the choke......
the choke bolts onto the side of the carb..

SP

Diggman33 · 10-01-2008, 07:58 PM

Just a quick end of season follow-up... I ended up getting the carb rebuilt, which resolved the idle/engine shake issue for about 3 trips. Since then, I've experienced more than my share of "flooded carb" starting problems - one of which had me sitting at the dock at the ramp for about an hour before I could get started (thankfully I invested in a marine charger/starter!). By this point in the season I now have to perform a start-up ritual, or I can plan on sitting around at the ramp for a long time.
I wonder if this is the proper start up proceedure for everyone with a carb -
Prior to start:
Pump Throttle several times
Set throttle to full
Crank engine
Once engine starts pull throttle back to about 1800rpm for a couple minutes
Gradually pull throttle back to neutral position to idle engine
(Whole process usually takes about 5 minutes before engine will idle without stalling)

Any thoughts?

seapuppy · 10-01-2008, 08:02 PM

well..when I had my 2455 bayliner sunbridge....i had to pump the throttle 3 times....set to 1/4 throttle...then start the engine which I had to let warm up or it would die....but it was the same....pump 3 times...and start....after that I could hit the throttle anytime during the weekend and it would fire right up.....

Sp

Diggman33 · 10-01-2008, 08:15 PM

Did you have to wait 10-15 minutes after it died to get it to fire up again? If I don't wait, it just prolongs the agony!

seapuppy · 10-01-2008, 08:23 PM

nope...just started cranking...if it stalls and floods...just open the throttle full and crank....be prepared to pull the throttle back immediately so you don't over rev the engine...but if it's flooding ...then you need to get the carb float set properly......

SP

zt260 · 10-02-2008, 02:20 PM

Had the same problem with carbeb 5.7 bayliner 2855 even when warm had to have throttle fully open,only found all this out when i had to spend the night in york on the boat because i couldnt get it going again,got it going about 5mins before marina boat came to tow me back the next morning cost me $250

ops:

ash

Diggman33 · 10-03-2008, 05:44 PM

That's terrible Ash! Sounds like the same scenario though... Do you recall what was wrong with the carb? As for me, Im leaning towards a bad choke, or float, but then again it could be a jetting issue as well - Im sure I'll find out $80 dollars later! (marina hourly rate)