New Dive Boat; The Deco - Suzuki motor issues

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Deco_Prokat

Recruit
Joined
May 13, 2009
Messages
5
I'm the proud new owner of a 2001 28' Prokat w/ twin 2001 Suzuki 225?s w/ EFI

Over the past few days I've had some issues with one of the motors. I've detailed as much as I can remember right now and was hoping someone here might be able to point me in the right direction.

Rt. Motor turns up fine, runs 5500rpm @ WOT
Lt. Motor ran fine @ 5500rpm initially @ WOT, and both motors settle between 42-4300rpm @ cruising speed.

After roughly 30 minutes of cruising, the Lt. motor dropped to 3000rpm and wouldn?t go above 3K even @ WOT.

After about 5 minutes of running, the rpm?s started to creep back up, and both motors went to 5500rpm again when testing WOT.

After a brief rest, rt. Motor continued running fine, and left motor was rough again @ 3000?ish rpm.
I left it full throttle and the rpms jumped after a minute or so to 3500, then 3800, then rose quickly back to 5500 @ wot.

Since then, I?ve replaced the spark plugs and primer bulbs b/c the left bulb looked like it might be leaking / dry rotted.

Today, when I pumped the primer bulb until it was full/firm, it began dumping fuel out of the air intake.

Any ideas? Any suggestions for a Suzuki OB newbie? :redface:

Thanks,
Deco_Prokat
 
cousinabe

cousinabe

Senior Chief Petty Officer
Joined
Nov 13, 2001
Messages
765
Re: New Dive Boat; The Deco - Suzuki motor issues

sounds like you may have a bad low pressure fuel pump or some sort of fuel restriction.

this would also cause your symptoms of running fine at WOT for a period of time and then not being able to fill the VST (vapor separator) with fuel fast enough to maintain.

Do you know the maint history of the motors?
Along with changing the fuel water separator filters,
I would clean the fuel strainer part #8 in figure 16.
Also, replace the high pressure filter, part #3 in figure 20.
http://store.brownspoint.com/dt225/2250103.asp
 
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SNye45

Petty Officer 2nd Class
Joined
Jan 22, 2008
Messages
113
Re: New Dive Boat; The Deco - Suzuki motor issues

I have a 2007 Suzuki 115 hp 4 stroke, (sorry if you already know this), however, I remember from reading the manual that if the engines computer chip senses any kind of problem, it automatically limits the rev range to no more than 3,000 rpm, to protect itself from anymore damage.

In other words the engine going down to 3000rpm is perfectly normal.
I realize this doesn't resolve your existing problem, good luck resolving it.
 
D

Deco_Prokat

Recruit
Joined
May 13, 2009
Messages
5
Re: New Dive Boat; The Deco - Suzuki motor issues

cousinabe said:
sounds like you may have a bad low pressure fuel pump or some sort of fuel restriction.

this would also cause your symptoms of running fine at WOT for a period of time and then not being able to fill the VST (vapor separator) with fuel fast enough to maintain.

Do you know the maint history of the motors?
Along with changing the fuel water separator filters,
I would clean the fuel strainer part #8 in figure 16.
Also, replace the high pressure filter, part #3 in figure 20.
http://store.brownspoint.com/dt225/2250103.asp
Click to expand...

Thanks for the input Abe!

We've changed the separator filters, cleaned the fuel strainer, and replaced the high pressure filter already.
I was told by a local OB mechanic that there is a low and a high pressure fuel pump, but that those pieces can run $100 and $400.00 each. I think we're going to try running the problematic motor off of the other fuel tank to see if we've got a restriction somewhere in the pickup, kink in the line (that we can't see) etc.

That link w/ the diagrams, parts, etc. is wonderful and will definitely come in handy. Thanks a bunch.
 
D

Deco_Prokat

Recruit
Joined
May 13, 2009
Messages
5
Re: New Dive Boat; The Deco - Suzuki motor issues

SNye45 said:
I have a 2007 Suzuki 115 hp 4 stroke, (sorry if you already know this), however, I remember from reading the manual that if the engines computer chip senses any kind of problem, it automatically limits the rev range to no more than 3,000 rpm, to protect itself from anymore damage.

In other words the engine going down to 3000rpm is perfectly normal.
I realize this doesn't resolve your existing problem, good luck resolving it.
Click to expand...


The rev limiter explains quite a bit. It was strange that it when the RPMs dropped, that it would settle right @ 3K, but your explanation makes sense and helps plenty. Hopefully it's not a bigger problem, but at least we have a better understanding of the situation now.

Thanks again, and I'll keep you all updated with the results.
 
D

Deco_Prokat

Recruit
Joined
May 13, 2009
Messages
5
Re: New Dive Boat; The Deco - Suzuki motor issues

cousinabe said:
ok.
parts 2-5 would take care of rebuilding the fuel pumps for around $22 each. fuel pumps do go... particularly the diaphragms, I replace/rebuild mine every 3 seasons on my yamaha 225 efi's.

http://store.brownspoint.com/dt225/fig016-2250103.asp
Click to expand...

Wow... For $22.00 a pop, this is a 'must do' option.

thanks again... This information has proved extremely helpful, and I'm putting fuel pump rebuilds @ the top of the list.
 
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