115 rebuilb bubble back or flat?

[And-Con]

OK i have two omc 115's which both came to me in a variety of pieces. one is from a jet boat(which is where the sum of the two engines will be replaced) one is from an outboard. The jet drive engine, which i am more or less not using(several issues with the block, but had a new starter and electrical) is a 1994 and i don't know the vintage of the outboard. the jet drive engine had a large bubble back exhaust manifold on it, where as the outboard had a relatively flat area between the cylinder banks (still the exhaust manifold, just much smaller) all things being the same and assuming i can fit the bubble back onto the other block i would just as soon continue using the bubble back. so since i didn't exactly pose a question in all that, here it is, do i try to keep the parts with the engine they came from, or can i mix and match freely in order to try to maintain the original configuration of the jet set up?

 

[ezeke]

Re: 115 rebuilb bubble back or flat?

The 115 with the flat back exhaust cover is probably from before 1987. The difference will be visible when the two covers are removed because the newer 115 TurboJet engine will have exhaust filler blocks and the flatback will not.

You can run the bubbleback covers without the filler blocks on the flatback block; It's a bit more complicated if you use the filler blocks. You should use the bubbleback covers for the extra cooling that they afford.

Be sure that the outboard block is from 1979 or newer or the crankshaft won't fit, among other problems.

 

[crb478]

Re: 115 rebuilb bubble back or flat?

Post the model number of the outboard to identify which year you have. Then you will be able to identify which parts will interchange. Some years will not interchange with others.

 

[And-Con]

Re: 115 rebuilb bubble back or flat?

OK i may sound really dumb but i have tried to figure out my year by any numbers i can get off the powerhead itself, since i don't have anything beyond that. on the block i would like to use, i found 2 sets of numbers, one off a quarter sized silver tab, which read g4227370 and one set stamped on the the block itself, which were much harder to read, but i believe to be 186l_4 02hv. the _ looks to be an 0, although it could be j,6,8,5,u, etc.

 

[tashasdaddy]

Re: 115 rebuilb bubble back or flat?

silver tab is serial #. we need model #. dealer may be able to help with serial #.

 

[emdsapmgr]

Re: 115 rebuilb bubble back or flat?

The serial number you posted is for a 97 90 hp engine. Both engines should have the same block size, 99.6 cubic inches. Both engines are propshaft rated hp. These engines are very similar. You should check for differences between them: type of fuel pump-the 90 may have been the non-VRO type, type of voltage regulator vs rectifier only. The 115 bubbleback will have larger-throated carbs to make more hp. Both engines use the same heads.

 

[And-Con]

Re: 115 rebuilb bubble back or flat?

thank you for the advice i will be looking up what parts are interchangeable now, and really all im using of the 90 is the block, the carbs from the 115 are getting rebuilt, 115 had new wiring as previously mentioned the 115 came with a fuel pump, and the 90 didn't, so its going to get that, etc. Really the 90(seller said it was a 115 oops) came to me as a short block(albeit in pieces) but all the other parts from the 115 are in good shape, so i should be able to piece a working engine together. just a side note but would anyone on here believe i got the replacement block (albeit already bored larger, thus needing a new piston) for less than the shop fees to fix where the po broke off 5(yikes) head bolts.