Volvo 250b

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Williediesel

Cadet
Joined
Apr 28, 2013
Messages
7
Hello at what hours should you be ready for a rebuild or repower
I got a 84 bayliner I'm getting a ticking noise around the overhead cam area
In the water I got to around 4000 rpms and the engine backed down to 3000 rpms. By itself ? But on the muffs I got her punched at 5000 rpms for 15 mins no problem. Tune up maybe ? Any ideas thanks
 
Howard Sterndrive

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Volvo 250b

you can take half the plug wires off and it will still turn 5000rpm with no load. Even with half the pistons removed.
Did you really run it for 15 minutes at 5000 rpms on muffs? That may have shortened it's life substantially.

Start with a compression test.
 
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Williediesel

Cadet
Joined
Apr 28, 2013
Messages
7
Re: Volvo 250b

I'm sorry I mis spoke 4400 rpm
Is what I ran the engine at on the muffs
It's what it's rated for but under load at 4400 rpm it drops to 3000 rpm by itself ? Tired engine ? Any info would help thank you
 
Howard Sterndrive

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Volvo 250b

start with a compression test, then on to fuel and ignition system tune-up/testing.

Engines do not like to run at high rpm with no load. You are risking catastrophic failure.
Some techs refer to "pistons wanting to swap holes". An engine is designed to run fast, but with resistance on the rotating mass, not free revving. Top piston rings can be broken when the venture into territory at the top of the cylinder where they are usually kept away by combustion load.
Also your water pump impeller may cavitate and fail unless you have the mother of all garden hoses supplying water. Most residential water systems do not supply sufficient water for that rpm. There are warnings in service manuals usually saying keep it below 1500 or 2000 rpm on muffs.
 
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