Boatmad.com


Reply
 
Thread Tools Display Modes
 
Old 21-10-2013, 07:15 PM   #1
Registered User
 

Join Date: Apr 2012
Posts: 53
200hp not performing

Aving some Eire greif

My mildly tuned 200 hp motor is slow

Run it yesterday not right,,, check comp readings 115 to 120. So all is well running prop as always run, but stuck out at 6100 rpm. It used to hit 7k n be safe

Can not see what is a do , any ideas what may be a miss,,,,

Running modified stator and lightened fly wheel carbs where set proffesionaly last year , only thing I have not tried is swapping out the fuel,,,,can the octane rating make this difference,[/QUOTE]
__________________

nugent is offline   Reply With Quote
Old 21-10-2013, 08:37 PM   #2
Registered User
 

Join Date: May 2009
Posts: 496
Quote:
Originally Posted by nugent View Post
Aving some Eire greif

My mildly tuned 200 hp motor is slow

Run it yesterday not right,,, check comp readings 115 to 120. So all is well running prop as always run, but stuck out at 6100 rpm. It used to hit 7k n be safe

Can not see what is a do , any ideas what may be a miss,,,,

Running modified stator and lightened fly wheel carbs where set proffesionaly last year , only thing I have not tried is swapping out the fuel,,,,can the octane rating make this difference,
[/QUOTE]

Not sure about engines, but one thing I do know and that is modern petrol is s**t and goes off very quickly depending on how it it stored. Did you have a mix with old/stale fuel? It can make big difference on power.
__________________

PerformanceDodge is offline   Reply With Quote
Old 21-10-2013, 09:20 PM   #3
Registered User
 
Hydrostream's Avatar
 
Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin

Join Date: May 2004
Location: Dublin
Posts: 1,803
Would think 115psi is a little low for a tuned motor. What engine is it?
And yeah if the petrol is old it can run pretty poorly!
__________________
www.powermarine.ie

[SIGPIC][/SIGPIC]
Hydrostream is offline   Reply With Quote
Old 21-10-2013, 10:44 PM   #4
Registered User
 
Country: uk
Location: salcombe
Occupation: semi retired
Interests: racing(middle east class 3 6l)
Boat name: still no worries
Boat make: phantom18
Engines: 2.5 efi
Cruising area: salcombe

Join Date: Dec 2007
Location: salcombe
Posts: 499
Try an earth wire on one of the coils, I had a bad one once
still no worries is offline   Reply With Quote
Old 22-10-2013, 11:35 AM   #5
Registered User
 
Country: UK
Location: Gosport
Occupation: Own a small building firm.
Interests: Boats, kids and looking after the Wife HaHa
Boat name: Shamu
Boat make: Banana Shark 770
Engines: Mercury XS300
Cruising area: Solent

Join Date: Aug 2013
Location: Gosport
Posts: 368
Quote:
Originally Posted by nugent View Post
Aving some Eire greif

My mildly tuned 200 hp motor is slow

Run it yesterday not right,,, check comp readings 115 to 120. So all is well running prop as always run, but stuck out at 6100 rpm. It used to hit 7k n be safe

Can not see what is a do , any ideas what may be a miss,,,,

Running modified stator and lightened fly wheel carbs where set proffesionaly last year , only thing I have not tried is swapping out the fuel,,,,can the octane rating make this difference,
[/QUOTE]
Banana Shark Dave is offline   Reply With Quote
Old 22-10-2013, 11:39 AM   #6
Registered User
 
Country: UK
Location: Gosport
Occupation: Own a small building firm.
Interests: Boats, kids and looking after the Wife HaHa
Boat name: Shamu
Boat make: Banana Shark 770
Engines: Mercury XS300
Cruising area: Solent

Join Date: Aug 2013
Location: Gosport
Posts: 368
Quote:
Originally Posted by nugent View Post
Aving some Eire greif

My mildly tuned 200 hp motor is slow

Run it yesterday not right,,, check comp readings 115 to 120. So all is well running prop as always run, but stuck out at 6100 rpm. It used to hit 7k n be safe

Can not see what is a do , any ideas what may be a miss,,,,

Running modified stator and lightened fly wheel carbs where set proffesionaly last year , only thing I have not tried is swapping out the fuel,,,,can the octane rating make this difference,
[/QUOTE]

Go buy some shell 99 octane, the BP premium fuel is only 97 and your problems stand a high chance of being solved. When I was racing we bought our fuel on the day and what was left over was used for practice. Any fuel older than a couple of months was poured in my mates car (two stroke oil and all).
Banana Shark Dave is offline   Reply With Quote
Old 22-10-2013, 06:28 PM   #7
Registered User
 

Join Date: Apr 2012
Posts: 53
Will give it a go

I think it's fuel related also
nugent is offline   Reply With Quote
Old 27-10-2013, 10:03 PM   #8
Registered User
 
Country: Uk
Location: Poole Dorset
Occupation: Marine engineer
Interests: Model boats and mercury v6
Engines: Mercury v6
Cruising area: Poole

Join Date: Jul 2011
Location: Poole Dorset
Posts: 1,770
Poor running

Sounds to me like you don't want your engine to last As you say it is mildly tuned a standard 200 Should only Rev to 5600 If you are running a standard fuel pump Ie the little square Diaphragm pump You are lucky to get 6100 rev As it We'll Run very lean To run over 6000 You need to run Electric fuel pumps And Bigger Jets In the carbs and more oil To be safe And your compressions are a little Low Should be a minimum of 125psi Hope this information helps as no one else has mentioned fuel pump And I ran some to 240hp mercury And they would not run with small pumps I Put electric pumps on and they ran great But I had heavy duty Conrods and standard 200 conrod Will not want to run for long At over 6000 So think you should keep this Things in mind if thay hav not been done
Sam1cats is offline   Reply With Quote
Old 28-10-2013, 08:25 PM   #9
Registered User
 

Join Date: Apr 2012
Posts: 53
Quote:
Originally Posted by Sam1cats View Post
Sounds to me like you don't want your engine to last As you say it is mildly tuned a standard 200 Should only Rev to 5600 If you are running a standard fuel pump Ie the little square Diaphragm pump You are lucky to get 6100 rev As it We'll Run very lean To run over 6000 You need to run Electric fuel pumps And Bigger Jets In the carbs and more oil To be safe And your compressions are a little Low Should be a minimum of 125psi Hope this information helps as no one else has mentioned fuel pump And I ran some to 240hp mercury And they would not run with small pumps I Put electric pumps on and they ran great But I had heavy duty Conrods and standard 200 conrod Will not want to run for long At over 6000 So think you should keep this Things in mind if thay hav not been done
Many thanks for this, not sure of all mods done to it , it was done my nick marsh down Cornwall two years ago and has allways run as stated until now for no reason, not been back at it yet,, it's fuel or ht side I think, fuel pump does not look std merc unit but still not electric, oil block of fitted and on pre mix,
nugent is offline   Reply With Quote
Old 28-10-2013, 08:29 PM   #10
Registered User
 
Country: uk
Location: salcombe
Occupation: semi retired
Interests: racing(middle east class 3 6l)
Boat name: still no worries
Boat make: phantom18
Engines: 2.5 efi
Cruising area: salcombe

Join Date: Dec 2007
Location: salcombe
Posts: 499
Take it down to nic's he will sort it !
still no worries is offline   Reply With Quote
Old 11-11-2013, 10:21 AM   #11
Registered User
 

Join Date: Apr 2012
Posts: 53
For the record ,,
It was a plug cap,,, All swapped out n running as sweet as
__________________

nugent is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3

All times are GMT +1. The time now is 05:17 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
×