So, bought a 2006 305 GXI with a cracked block. Engine # 3869309 5.0 GXI-F. Volvo wanted $5500 for a long block, at the time I thought that was a bit much. I removed the engine and tried to source a replacement. During my research, I was told several times that a 350 would be a 'bolt in" application, "we do it all the time" - direct quote from a local marine engine supplier. So I got a new 350 short block, and used the old (100.7 hours) heads, cam, flywheel, intake, etc. Now it starts right up BUT:
Runs rough at idle. Surges up and down 100- 400 rpms, sometime settles down to a consistent 700-800 rpm idle. With no load and a little throttle, it was surging 400-600 rpms, then same thing, sometimes settling down. Test ran it in the water, same thing at about 3000 rpms- runs smooth, but surges up and down. When I back off on the throttle from 3000 rpms it dies every time.
I have read this thread: http://forums.iboats.com/volvo-pent...volvo-penta-305-350-running-rough-310708.html . BUT on mine, the ECM is not programmable; apparently it is an "E" type and Volvo made it so that it is not changeable? This is what I have been told by the boys that should know including the dealer.
Speaking of the dealer- They tell me that a new ECM is $1500, and might not work, "too many variables" they say. I told them there are no variables- I have a 350 block and everything else is from the original engine. Their response? If it doesn't work there are no returns on electronics. Thanks guys.
I have heard everything from I need to get a new- programmable- ECM (which would mean a new harness also) and program it, to "get a 305 and put it in". What if it isn't the block size though? It is reading no codes, and we are at a loss. Everyone has a different opinion; I have also been told that the computer takes a while to "learn" the engine and just to run it a while. I could write a book just on all the different theories.
So, next steps? Thanks in advance.
edit: full set of numbers listed on engine
3869309
4012191556
5.0 GXI-F
Runs rough at idle. Surges up and down 100- 400 rpms, sometime settles down to a consistent 700-800 rpm idle. With no load and a little throttle, it was surging 400-600 rpms, then same thing, sometimes settling down. Test ran it in the water, same thing at about 3000 rpms- runs smooth, but surges up and down. When I back off on the throttle from 3000 rpms it dies every time.
I have read this thread: http://forums.iboats.com/volvo-pent...volvo-penta-305-350-running-rough-310708.html . BUT on mine, the ECM is not programmable; apparently it is an "E" type and Volvo made it so that it is not changeable? This is what I have been told by the boys that should know including the dealer.
Speaking of the dealer- They tell me that a new ECM is $1500, and might not work, "too many variables" they say. I told them there are no variables- I have a 350 block and everything else is from the original engine. Their response? If it doesn't work there are no returns on electronics. Thanks guys.
I have heard everything from I need to get a new- programmable- ECM (which would mean a new harness also) and program it, to "get a 305 and put it in". What if it isn't the block size though? It is reading no codes, and we are at a loss. Everyone has a different opinion; I have also been told that the computer takes a while to "learn" the engine and just to run it a while. I could write a book just on all the different theories.
So, next steps? Thanks in advance.
edit: full set of numbers listed on engine
3869309
4012191556
5.0 GXI-F
