Yanmar 4lha STZP & Bravo 1 - 2004

[SampoSam]

Hi All,

I am currently having issues with my 2004 Monterey 250 cr where at full throttle i am only getting 11 knots. Was getting around 24 knots but gradually been losing top speed over 12 months . I am running a 240 HP Yanmar diesel ( 476 hours) with a Bravo 1 and 14.5" diameter with 24inch pitch 4 blade prop . Had the turbo ( which was told partially blocked ) , intercooler and oil cooler refurbed but made no difference. Engines starts first time and runs smooth but have noticed some black smoke since Turbo etc refitted..which is new. Been told it may be a fuel delivery problem or rubber driveshaft slipping ? - also been told could be prop size some say should be higher 28inch pitch others say much lower 19"- i m sceptical as had above 20 knots with the current blade 12-18 months ago?

I can't find anyone with the same boat and engine/drive configuration so can't check other i have the correct prop ?

Any assistance greatly appreciated !

 

[Rareplank]

Hi

That’s the correct prop we installed when fitting that engine to those boats. Guess you have a clean hull to start with?

check hose between turbo and intercooler is in good order.

The gaskets on intercooler were they all replaced?

Have you checked in the engine bay? The elbows on the exhaust side of turbo can fail/crack giving lack of power. You will notice soot in the bay.

 

[Rareplank]

Hi

That’s the correct prop we installed when fitting that engine to those boats. Guess you have a clean hull to start with?

check hose between turbo and intercooler is in good order.

The gaskets on intercooler were they all replaced?

Have you checked in the engine bay? The elbows on the exhaust side of turbo can fail/crack giving lack of power. You will notice soot in the bay.

Hi All,

I am currently having issues with my 2004 Monterey 250 cr where at full throttle i am only getting 11 knots. Was getting around 24 knots but gradually been losing top speed over 12 months . I am running a 240 HP Yanmar diesel ( 476 hours) with a Bravo 1 and 14.5" diameter with 24inch pitch 4 blade prop . Had the turbo ( which was told partially blocked ) , intercooler and oil cooler refurbed but made no difference. Engines starts first time and runs smooth but have noticed some black smoke since Turbo etc refitted..which is new. Been told it may be a fuel delivery problem or rubber driveshaft slipping ? - also been told could be prop size some say should be higher 28inch pitch others say much lower 19"- i m sceptical as had above 20 knots with the current blade 12-18 months ago?

I can't find anyone with the same boat and engine/drive configuration so can't check other i have the correct prop ?

Any assistance greatly appreciated !

Are you getting full revs at 11knots? Could also be prop bush. Should have the uprated metal spline with 4 rubber strips as opposed to the plastic hub

 

[SampoSam]

Hi

That’s the correct prop we installed when fitting that engine to those boats. Guess you have a clean hull to start with?

check hose between turbo and intercooler is in good order.

The gaskets on intercooler were they all replaced?

Have you checked in the engine bay? The elbows on the exhaust side of turbo can fail/crack giving lack of power. You will notice soot in the bay.

Thanks good to know its got the correct prop finally ! - assume you use to work for southwest marine ? - i will check the hose between turbo and intercooler as well as the exhaust side ( i am getting black soot) assume the gaskets were all replaced on intercooler as this has been fully refurbed but will ask the engineer- yes checked the hull and all clean - any other suggestions greatly received but will let you know how i get on the above in the meantime - would be great to make contact with you directly to discuss but not sure how we do that on here ?

 

[SampoSam]

Are you getting full revs at 11knots? Could also be prop bush. Should have the uprated metal spline with 4 rubber strips as opposed to the plastic hub

yes as metal spline so don't think its a slipped hub ?

 

[burgundyben]

Thanks good to know its got the correct prop finally ! - assume you use to work for southwest marine ? - i will check the hose between turbo and intercooler as well as the exhaust side ( i am getting black soot) assume the gaskets were all replaced on intercooler as this has been fully refurbed but will ask the engineer- yes checked the hull and all clean - any other suggestions greatly received but will let you know how i get on the above in the meantime - would be great to make contact with you directly to discuss but not sure how we do that on here ?

Has she been in the water for 12 months?

When you say hull is clean, can you expand on why think that? When was she last lifted and jet washed?

 

[oldgit]

Has she been in the water for 12 months?

When you say hull is clean, can you expand on why think that? When was she last lifted and jet washed?

+1
Extraordinary year for fouling.
Examples of boats being anti-fouled in May and lots of slime/weed around 3/4 months later.
Possibly due to lack of early season use curtailed by rubbish weather ?

Have just completed oil/filter change on my pair of Yanmar 4 HASTE, suprised to find that the airfilters are washable and easy to remove,
unlike the paper cartridge air filters of my previous my Volvo Penta engines.

 

[SampoSam]

+1
Extraordinary year for fouling.
Examples of boats being anti-fouled in May and lots of slime/weed around 3/4 months later.
Possibly due to lack of early season use curtailed by rubbish weather ?

Have just completed oil/filter change on my pair of Yanmar 4 HASTE, suprised to find that the airfilters are washable and easy to remove,
unlike the paper cartridge air filters of my previous my Volvo Penta engines.

Thanks yes took her out last week and inspected the hull - some very small barnacles but nothing major

 

[penfold]

It doesn't take much, that growth needs to be removed, especially if there's any on the prop.

 

[SampoSam]

Well seems it was a partially blocked injector and badly adjusted tappet clearance - i am for it waiting to be finished on Monday and fingers crossed it will finally get to the correct ( greater than 11 knots that it !) - will confirm on the forum next week

 

[oldgit]

badly adjusted tappet clearance -

Initial check after 250 hours or 1 year.
Then every 1000 hours or 4 years.

https://www.yanmar.com › com › operationmanual

Yanmar would appear to be way ahead of the crowd in the amount of FOC manuals online with detailed information on parts/servicing and owner repair.
Available directly FOC from the Yanmar website.

 

[SampoSam]

So update now having refurbed an injector that wasn't spraying correctly as well as adjusting tappets that were way out and refurbed the exhaust elbow from the turbo it made no difference at all!- The next step is that maybe an issue with the fuel injector pump which has now been removed and being checked. If no issue there don't know where to go from there :-(

 

[QBhoy]

yes as metal spline so don't think its a slipped hub ?

Is there not still a sacrificial rubber bush surrounding the spline in the prop ? I’m aware the B2 prop does not have the insert type hub, but almost sure it still features a sacrificial arrangement in around that area.

 

[SampoSam]

Is there not still a sacrificial rubber bush surrounding the spline in the prop ? I’m aware the B2 prop does not have the insert type hub, but almost sure it still features a sacrificial arrangement in around that area.

Thanks . I have tried a different prop and not change so i think i can rule that out unless rubber bushes on both had gone ?

 

[QBhoy]

Ok. So I presumed for some reason that this was a bravo 2. But now realised she’s a bravo 1. This being the case, you should have a sacrificial hub kit insert, especially if she has a OEM Mercury prop. Can I just confirm she is definitely a bravo 1 and also ask what the gear ratio might be ? That’s a fair amount of pitch you have there. Unusual even number of pitch too, if she has a oem prop on her. Is she a specific diesel bravo 1 ? She must have a fairly unusually low ratio for her to be expected to be capable of turning a pitch like that.

 

[Rareplank]

From memory we fitted Bravo 1 X 1.65:1 running 24” bravo 1 4 blade. This prop should have uprated metal bush with the 4 rubber strips not the plastic hub kit. Bravo 2x we fitted on later boats at 1.81:1

 

[Rareplank]

Check you are getting full revs with a handheld tacho and don’t assume off the dash.

 

[SampoSam]

Check you are getting full revs with a handheld tacho and don’t assume off the dash.

Many thanks. Regarding the revs i understand that there is a mechanical cut out at 3,400 and Tacho shows unto 4000. Apparently the Tachos are not calibrated to the diesel engines ( made for petrol engine) plan to test the correct revs with handheld soon and will let you know. My guess is that Tacho is showing around 700 rpm over. Yes running Bravo 1 but couldn't find ratio was thinking 1:5 but you might be correct at 1:65. Yes still has 4 blade 24" prop on it which i am led to believe is correct. Great that you were involved in the binding of these boats !- thanks again for your help

 

[Rareplank]

It could be a 1.5:1 there were a couple we did running that ratio. Going to guess your an 03/4 boat?

 

[SampoSam]

It could be a 1.5:1 there were a couple we did running that ratio. Going to guess your an 03/4 boat?

yes correct 2004 !