Broken valve spring

[henry1357]

Hi everyone

Loud tapping rattling while out today, crawled back in on idle.

Took valve cover off and have a broken valve spring.

What do I do now just replace spring or is it more serious

Thanks in advance

Henry

 

[Don S]

Re: Broken valve spring

Replace the spring, do a compression test and see what happens.

 

[henry1357]

Re: Broken valve spring

Thanks don

I am on holiday in spain until next week where boat is kept
Could I replace spring and run as I have no means to do compression test or am I asking for trouble

Regards
Henry

 

[LAC_STS]

Re: Broken valve spring

You can buy a compression tester gauge for like $20. All you do is take the spark plug out and screw the compression tester gauge in there then crank the engine and read the reading.

Oh yea. and unplug the lead from the coil so the engine doesnt start. You just want it to crank.

Not hard at all and will tell you if your good.

 

[henry1357]

Re: Broken valve spring

Thanks don

Thought you needed compressed air for that, I will buy one Monday, what reading should I see.

Is it likely that I've bent a valve , valve stem is about an inch out of the head.

Was making quite a clatter running back to boat yard.

Thanks Henry

 

[Idlespeedonly]

Re: Broken valve spring

Its hard to say if you bent a valve or not. As for the pressure, check all cylinders then compare them. They should all be within 10%.

 

[Eric 3.7LX Alpha 1]

Re: Broken valve spring

Your gonna have to get a tool (valve spring compressor) unless you have serious gorilla fingers!!! to compress the spring down to remove the keeper that holds the spring on the valve. Just incase you didn't know....

You tube replacing a valve spring while on the engine to see videos of it).

You can rent one from many auto parts stores or get one from harbor freight if you are close by one for cheap money.

I'd post a link for the service manual for you to reference the job... and what compression numbers you should see with that compression tester..... but I have no Idea what engine or year or drive you are running. Seems like everyone is afraid to post it these days...

 

[Idlespeedonly]

Re: Broken valve spring

Hard to say if you bent a valve. As for the readings, che k all of the cylinders. They should be within 10%.
Better than that, send me a plane ticket, ill do it for you. I will give it a tune up and a wash and wax also.

 

[Oshkosh1]

Re: Broken valve spring

or get one from harbor freight if you are close by one for cheap money.

Do they have those in Spain??

 

[henry1357]

Re: Broken valve spring

Hi Eric

Thanks don

It's a merc v6 4.3 1998 with alpha one 2nd gen

Regards
Henry

 

[Idlespeedonly]

Re: Broken valve spring

To touch on what eric said, you will have to keep the valve from falling into the cylinder. Two options are fill the cylinder with compressed air or fill the cylinder with rope. I prefer rope. Check out youtube like eric mentioned.

 

[Eric 3.7LX Alpha 1]

Re: Broken valve spring

Do they have those in Spain??

Ya never know these days!!!

everyone likes cheap tools that are good for one time use!!!!

 

[Oshkosh1]

Re: Broken valve spring

Ya never know these days!!!

everyone likes cheap tools that are good for one time use!!!!

I bought a "cheap" 110v wire feed to keep at my cabin. I've used it twice. Once to repair a bracket holding my mower deck to the frame(saved $70) and a friction disk on an old Toro snowblower(priceless...can't find 'em). Took the advice of a professional welder and bought good wire...made a world of difference! A friend borrowed it to weld up a trailer also. Needless to say it's paid for itself many times over! Oh...and their sockets aren't bad either. Wouldn't touch their power tools with a dead skunk...but some of the stuff there is ok.

 

[henry1357]

Re: Broken valve spring

Hi everyone

The spring that is broken is the first one on port side from the front of engine(bow end) is this the exhaust or inlet valve.
Regards
Henry

 

[Eric 3.7LX Alpha 1]

Re: Broken valve spring

Here's that link to service manual# 25, you can't download it but can flip thru the pages and print any as needed.
http://boatinfo.no/lib/mercruiser/manuals/mercruiser25.html#/0

.

 

[spdracr39]

Re: Broken valve spring

Wondering why it broke in the first place. Are you running high rpm's? Max at WOT is 4400-4800.

 

[henry1357]

Re: Broken valve spring

Hi

Wot is in range not sure why it broke, boat has had little use before I bought it and it is 14 years old
If that spring was fully compressed for a year or two could that weaken it

Regards
Henry

 

[henry1357]

Re: Broken valve spring

Here's that link to service manual# 25, you can't download it but can flip thru the pages and print any as needed.
http://boatinfo.no/lib/mercruiser/manuals/mercruiser25.html#/0

.

Hi thanks for manual link