2002 Mercruiser 5.7 250hp engine noise

[achris]

That's a 5 litre MPI engine, not a 5.7...

NGK plugs... TR55IX, gap - 60 thou.

Chris........

 

[jabfd]

No it’s a 5.7 l with a 2 barrel carb

 

[achris]

Used a different serial number look up site and got a different result... Sorry for the confusion...



Gap is the same, 0.060"

 

[jabfd]

Thank you

 

[alldodge]

Chris, this comes up many times and would like to know just how to determine.

Manual 24 is for carb motors and list .045 and does list some things in the serial number range above 0L619000 and higher, but is not clear as to how high it does go (Models covered is blank)

Manual 31 list 2001 and higher motors but are all MPI and do list gap at .060 (Models covered has SN)

 

[achris]

I use multiple sources and the manuals. I often interpolate between the manuals. eg. Manual 24 lists serial number 0L619000 and above, with no cut off. The next later manual for SBCs lists serial numbers 0M300000 and above. Therefore, manual 24 cut off must be 0M299999... easy

 

[alldodge]

Thanks for the SN range, going to record that

, but manual 24 shows MR43LTS and .045, this is what caught my thought

 

[jabfd]

Ok everyone so I replaced the wire and cap and rotor but the problem is still there can’t really get over 3400 rpm. When I took a plug off it was gaped around 35 thousands so Iam a little confused. The current plugs are champion rs12yc new plugs are ngk I haven’t installed the plugs because not sure if it supposed to 35 or 45 or 60 motor serial # m623660. I think the engine is a 2002 model year 2 barrel carb and 5.7 L 250 hp any help would be great thank you in advance

 

[achris]

What are the NGK plugs? (the numbers on them)

 

[jabfd]

Ngk Bpr6efs

 

[jabfd]

That’s is what my local mercruiser gave me for plug

 

[achris]

NGK BPR6EFS

45 thou...

The NGK BPR6EFS is a standard copper spark plug, the platinum equivalent is the TR6IX... (and is a better spark plug. )

 

[jabfd]

Ok I will set them to 45 thank you for all your help

 

[alldodge]

problem is still there can’t really get over 3400 rpm.

This is probably more the the just a plug issue.
Did this just happen or been going on for a while?
Is it a new to you boat?

 

[jabfd]

It started about 3 weeks ago I do have A barnacles on the bottom and this could be some what the problem I took the boat out today and now when I try to go over 3400 rpm I have a clacking noise like the carb is clacking or something on to another problem I guess

 

[alldodge]

Can you put the boat on a trailer and pull the drive?

 

[jabfd]

Yes I can what are your thought ? do you think some is wrong with the drive if I drop the rpm to around 3000 rpm no clacking sound

 

[jabfd]

Also I did have drive out before I put the boat in the water unjoints were grease gimbal was fine and new bellows installed

 

[alldodge]

I don't know what "clacking" means but if prior to 3 weeks ago you could get full WOT (44-4600 rpm) and now your not. Barnacles are an issue but I don't see how this would happen all at once.

Guess I need a better understanding of clacking

 

[jabfd]

When I first put the boat in the water clean bottom 4 people on board 3/4 tank of fuel boat would get to 4400 wot planed and cruise at 3800 at 20 knots
I added some gear in the boat put 30 gals of water in the boat and I was just able to get to 3800rpm took boat to the beach scraped bottom and on the way back got up to 4000rpm boat also gotclode to 19 knots
didn’t use boat for three weeks now but does want to go over 3400 and after 3000 rpm I hear a clacking sound . At first I thought it was pinging noise I changed the filter there was some water separatation in the fuel from the filter but the filter was almost two years old fill tank when and added k100 additives and startron. Problem is still there changed plugs wires and cap still there . Sorry for the long message