2006 sportster 155, locked up engine, interchange questions

[anesthes]

Picked up my first 4-tec. All of my other doo's are 2 stroke. I think I did ok money wise, fairly good condition boat with a locked up 155. It's a 2006.

I have not even had a chance to inspect the engine myself, but the seller said it locked up. He removed the plugs, jet pump, and tried rotating the engine and it's frozen. Said this happened while driving, and he thinks the timing chain broke. I probably need to remove the engine from the boat to tear it down enough to determine the failure, but assuming the block/rotating assembly exploded, I'm curious which 155s are direct interchange with this. I googled for hours and hours and I couldn't really find what I was looking for, what year to year differences exist, etc. I've seen engines for sale from PWC from 04+, and I've seen reman long blocks on ebay that specify specific years.

Anyone have some insight to help point me in the right direction? I'm thinking probably just buy a long block, although if someone was parting out a complete engine from a running PWC I'd likely consider that as well if it was local.

But I assume there are some year to year differences ? I know on the 2 stroke stuff the magnetos and pickups are different between some years, which make things interesting.

Thanks!

 

[spinyard]

How much you pay for it? Welcome to the 4tec world even if you buy a used motor prepare to buy a new timing chain, valves, and a new head gasket for whatever motor you buy. Tear down yours first to see exactly how bad it is then post some pics here.

 

[anesthes]

How much you pay for it? Welcome to the 4tec world even if you buy a used motor prepare to buy a new timing chain, valves, and a new head gasket for whatever motor you buy. Tear down yours first to see exactly how bad it is then post some pics here.

I paid $2k for the boat and trailer.

I did watch some videos of 4-tec engines with broken timing chains, and I was surprised that the only real failure was valves. Might be interesting to see if this one could be saved. I may pull the valve cover this week just to see if the timing chain did break, or if it dropped a valve, etc.

 

[anesthes]

Piston closest to the bow blew up. Maybe water intrusion? I took the valve cover off, timing chain fine. Valves not broken. Send my scope down each plug hole. Check this out:

 

[Hol890]

I bought a used one but never had such issue.

 

[spinyard]

It’s really hard to tell by that picture. Best bet is to find a used motor of eBay or something and build it up yourself maybe you got lucky and the block and crank is still good. Did it drop a valve ?

 

[anesthes]

It’s really hard to tell by that picture. Best bet is to find a used motor of eBay or something and build it up yourself maybe you got lucky and the block and crank is still good. Did it drop a valve ?

No, valves seem fine. Timing chain fine. I'm thinking water got in that cylinder or maybe just detonation. I'll check the injectors on my injector machine. I've got a bunch of stuff in the shop right now, but maybe in about 3-4 weeks I'll be able to get it in for a tear down.

 

[ski-d00]

All the 155 4tec engines are basically the same or can be easily interchanged with minor changes from 2002-2016. All the supercharged engines are not interchangeable due to different pistons and compression ratio. The 130s are almost the same except for a different camshaft which you could swap yours into easily.

Since you have a boat and not a pwc, your 06 is most likely the original style engine and crank with the old style TOPS system and stator wires coming out of the PTO housing at 12 o'clock. The simplest swap for you will be to use the 02-05 4tec 155 but the best option is to use the newest one you can find with the lowest hours but make sure the PTO housing is included because they are different on the newer engines. To use a newer block is a simple swap but depending what exactly accessories from what years you use will determine what modifications are necessary.

You can try to rebuild yours but usually the block gets trashed when a piston lets go but at least worth tearing down and inspecting.