Merc 4.3 6cyl RPM's jumping? not started 2 years

[Fireman431]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

The high RPM's...was the engine fully warmed up? Does it have the electric choke (sticking)?

Check for any vacuum leaks. New rubber vacuum lines are cheap and will save a lot of headaches.

 

[bomar76]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

The high RPM's...was the engine fully warmed up? Does it have the electric choke (sticking)?

Check for any vacuum leaks. New rubber vacuum lines are cheap and will save a lot of headaches.

There should not be ANY vacuum lines on a marine engine made in the last 50 years.

 

[dolemite_1]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

Ok the serial number is........ 0F075668

Transom and Drive are 443L1003 and 0f103610 or vice versa.


So figured out the back light not working- just not lubed so was sticking and not going deep enough.

Blower still a mystery- light on the button comes on but no blower-- motor maybe?

Still can't find the spot where the little carb filter goes followed the gas line and just don"t see it. Un did the connection right at the carb-- no luck.

Power steering piston (?) shot -- told by previous owner, looking to fix that. Is that a hard job in your guys opinion?

Being told the trim gauge and outdrive only coming up with trailer button is pretty common.

Thx again for all your guys help. I truly appreciate it.

 

[Don S]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

You're in luck, you have the newer balance shaft engine and need manual #18
Here is the link, and only 12 MB.

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/18/18covr2.pdf

 

[dolemite_1]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

Thank you for the link "The Don" . 638 pages-- hope it answers more of my questions than raises. haha

 

[dolemite_1]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

New question. I ran the engine idle for 15 min then took it up to about 2000 rpms for a sec let it come back down and had what seems like carbon knock for about 10 seconds. Is this common?

thx

 

[Maclin]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

I am not sure what carbon knock is, but it sounds like to me you may have an oil pressure issue.

 

[Don S]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

I'm not sure what a carbon knock is either, but it may be lifters rattling that you hear. Have you checked the oil level? Is it overfull?
If the oil level is too high and the crankshaft can hit it, it will aerate the oil and cause the lifters to become soft.

 

[Fireman431]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

There should not be ANY vacuum lines on a marine engine made in the last 50 years.

Don't tell that to the last 2 boats I sold. 82 Bayliner bowrider with a VP 140/280 and an 89 Capri. Both had Solex carbs with a vacuum line to the rear. I didn't know they weren't supposed to be there, I wonder if they did?

 

[Coors]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

New question. I ran the engine idle for 15 min then took it up to about 2000 rpms for a sec let it come back down and had what seems like carbon knock for about 10 seconds. Is this common?

thx

Dieseling?

 

[dolemite_1]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

Yes Coors Diesling, your right. I've always heard it by that name or carbon knock.
Basically when fuel in the engine is igniting with no spark after the engine is shut off -- whether it be by very hot chunks of carbon buildup in the combustion chamber, or fuel corruption, bad spark plugs etc...

I'm thinking it had to do with me revving the engine before shutting it off, since the oil level is on par. Any thoughts?

As for my blower not working do you think it's possible for the light on the swicth to be working and it still being an overall electrical issue. I am thinking it would probably be just a blown blower motor.

 

[Maclin]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

Ok, now that I know you revved it up then shut it off immediately I undertand what you meant. Actually that is the recipe to make it diesel or run-on.

 

[Coors]

Re: Merc 4.3 6cyl RPM's jumping? not started 2 years

Revving, lean mixture, timing will make it do that. Also, from running rich for too long will build carbon in the head.
Seafoam-google it, walmart has it.
Or just do the old coca cola trick- rev it and pour in coke in the carb; the water and sugar blow the carbon off the heads. (actually it is the water in the coke)