2005 230 Horizon 5.7 GXi rpm ?

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

Asked this in the engine, drive and prop forum.
Seemed to have lost some rpm/speed at full throttle.
GottWhat gave a good link to what this boat should do for rpm and speed at full throttle. (4600-5000 and 48-51)
I seem to have lost a 500-800 rpm. I changed fuel filter and it starts and runs fine.
Prop is factory and has been reconditioned.

Any advice would be great.

Thanks

rpengr · **Posted:** Wed Jun 17, 2015 1:56 pm

If your prop and hull are not the problem,
and it is otherwise running perfect,

Then I suspect not enough air going in, or not enough air going out:
- Throttle cable issue
- Exhaust Flapper issue or other exhaust blockage
- Worn Camshaft

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

I sure hope it's not the cam, ouch. How do I check the throttle cable?

rpengr · **Posted:** Wed Jun 17, 2015 2:34 pm

kirkj11 wrote:

I sure hope it's not the cam, ouch. How do I check the throttle cable?

I'm used to carburetors. Just take off the flame arrester and look at the butterfly to see if it is opening all the way at full throttle (without the engine running). Not sure if it is that easy on the fuel injected engines. Maybe somebody else will know if it is controlled by the computer...which could be affected by the TPS (Throttle position sensor).

Camshaft is not very likely on roller tappet engines (such as the Vortec Chevys). I've seen loss of power due to worn camshafts on aircraft engines with flat tappets. Lack of use allows rust on camshaft, which starts spalling and wear.

Look up "Exhaust Flapper" on this forum for more information on that topic. You can definitely loose 800 rpm if an exhaust flapper came loose and lodged in the lower exhaust passageway.

rpengr · **Posted:** Wed Jun 17, 2015 2:42 pm

Just one more thought: Could it be running on 7 cylinders instead of 8? (bad spark plug or wire)
(Diagnose by removing all plugs and looking for difference in color / carbon buildup / wet vs dry)

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

Thanks

I would think if only running on 7 cyl their would be a definite miss or hesitation and maybe even trouble starting.

afw200 · **Posted:** Wed Jun 17, 2015 3:00 pm

Highly unlikely I has anything to do with the camshaft. If you have not, do a compression check
on all cylinders, and report results. Then you will know what it is NOT.

rpengr · **Posted:** Wed Jun 17, 2015 3:08 pm

kirkj11 wrote:

Thanks

I would think if only running on 7 cyl their would be a definite miss or hesitation and maybe even trouble starting.

It could run smoothly on 7 cylinders if the 8th was not cutting in and out. But I would think this would loose more like 1000 rpm.

(Diagnose by removing all spark plugs and look for differences in color / carbon buildup / dry vs wet)

Did this problem start suddenly, or gradually over a long time?

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

More gradually I think. Just kinda noticed it last weekend when taking the boat back to the lift when just myself and son was in the it. Looked at tach and speedometer and thought, huh doesn't seem to be going as fast as I remember. Didn't really think much about it until driving home and started questioning it. I had pulled tubes and skiers all weekend so didn't really have it full throttle up to full speed until later.

I have a captains call so the exhaust is not restricted. But the air intake could be. Haven't cleaned that for sometime.

230 Mike · **Posted:** Mon Jun 22, 2015 3:41 am

There are no flappers in the exhaust on an '05, unless someone added them back in, which is highly unlikely.

This is also unlikely to be the cause, but something more obscure to consider: Volvo issued a service bulletin awhile back, to have the filter/screen removed from the input side of the fuel pressure regulator because they were becoming clogged (or there was a risk of that happening). There's a special clip that needs to be installed in it's place, part #21491831. I'd be willing to bet that most engines have not had this done.

http://www.marinepartsexpress.com/VP_Se ... ulator.pdf

Haddock_ · **Posted:** Mon Jun 22, 2015 8:22 am

230 Mike wrote:

There are no flappers in the exhaust on an '05, unless someone added them back in, which is highly unlikely.

This is also unlikely to be the cause, but something more obscure to consider: Volvo issued a service bulletin awhile back, to have the filter/screen removed from the input side of the fuel pressure regulator because they were becoming clogged (or there was a risk of that happening). There's a special clip that needs to be installed in it's place, part #21491831. I'd be willing to bet that most engines have not had this done.

http://www.marinepartsexpress.com/VP_Se ... ulator.pdf

Mine hadn't until I did it this winter.

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

Thanks Mike. I'll give that a try.

rpengr · **Posted:** Mon Jun 22, 2015 10:03 am

Haddock_ just had a similar problem that turned out to be a very dirty flame arrester:
http://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=14153&p=136697#p136697

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

I was going to check that, but didn't get a chance to get there this weekend.

Thanks again for all the input.

kirkj11 · **Joined:** Wed Oct 09, 2013 7:38 am **Posts:** 21

Update on rpm/speed problem. I cleaned to flame arrester. It was pretty dirty, looked like badass dust-bunnies in it. Used a high pressure washer, blew it out with air and let sit in sun for day.

Seemed to do the job. Picked up about 600 or so rpm and 7-10 mi/hr.

Thanks for all the help.

Happy boating!!!!!!!!

www.iFourWinns.com

2005 230 Horizon 5.7 GXi rpm ?

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