Mercruiser model #

[Glassport from Newport]

I just bought a 1991 bayliner Capri with a 4 cylinder mercruiser. The serial number for the engine is D610831. I'm trying to find out if it is a 3.0L or a 3.0LX. Whats the difference between the L and the LX? My engine has the Delco EST ignition (if that info helps). Thanks in advance for any help!

 

[Ron H.]

Re: Mercruiser model #

Trying to tune up my 3.0LX before putting her in cold storage and have come across a spark plug dilemna. Manual shows very different plugs for these two engines, although they are virtually the same engine.

One of the plugs is almost three times as long (inserted thread length) than the other. I have run both plug types in this engine and both sizes seem to work fine.

What is the difference between the 3.0L and the 3.0LX engine? I think it is only the igition system, but why would that effect plug length?

Which plug is better and why?

What is the big difference between long and short plugs anyway??

Thanks for any help!

Ran across this on another site...hope it helps

 

[Ron H.]

Re: Mercruiser model #

The 3.0 L an LX have 2 different head designs....the smaller port lx head uses a 3/4" reach plug, the l uses regular 1/2" reach....I too have seen the wrong plugs in these motors, in both combinations...good thing these are relatively low stress engines...LOL....sometimes measuring thread depth in the head is the only verification you have....

forgot the reply

 

[Glassport from Newport]

Re: Mercruiser model #

Thanks for your help guys. It's amazing all the little differences out there that don't seem to be documented or labled. As always I appreciate the help here on iboats.

 

[Don S]

Re: Mercruiser model #

It's a 1991 3.0L model #430B0001S

 

[Glassport from Newport]

Re: Mercruiser model #

Thanks Don! As always, you are a huge wealth of knowledge. You're very much appreciated.

 

[rocket350]

Re: Mercruiser model #

Don the hero on this site answered this for me a week or two ago. The L and LX are the same engine, but diferent heads. The L has is rated at 115hp, and the LX is rated at 135 hp.

The L is identical to the older 140 hp engines, but they rated the 140's at the engine, and the 115 is rated at the prop.

You say you have the EST ignition? I think I have this too. there is a square coil (opposed to the traditional round cylinder type) and the distributer is shaped almost like a half circle at the base. There is no seperate EMC box. The reason I ask is he manual says it is supposed to be timed at 1 BTDC. I put it at 1, and it would plane nicley, but I couldn't get much for rpm's. I could only get up to about 25mph. I timed it at 8 BTDC, and now she huals! It was at 33mph on choppy water and I had to back off, so I think I may be able to get 40mph on my 19' cuddy!

I am not trying to steal the thread newport, but if could pm me or whatever on your timing and what it is set at, I'd really appreciate it.