Need help identifying proper jets

[TroyHowell]

Here is the situation, I received this boat from my father in law who passed. I have re-built everything non motor related and it is a fairly nice boat now. The motor, I have yet to identify the year of is what I beleive to be an evinrude 115 hp probaly around the late 70's or early 80's. The carbs have the high speed jet in the bottom of the bowl with the lead shot above it, no other jet directly above the high speed. The jet size says 58 8, but my father in law frequented a boat junk yard and I can't even say if the carbs came off this engine. While underway the boat will accelerate to 5k then back off to 3500 rpm, if i push the choke in it will accelerate up for a second and then fall back off. I have reuilet the carbs and all fuel lines filters... I had to pull the high speed jets with an eazy out so will have to replace them, problem is I would like to get the correct jets to allow for maximum performance. I'm reading 54-67 on the jet size...any suggestions?

 

[will62]

Re: Need help identifying proper jets

I'm working on a '79 Johnson 85hp that had mismatched carbs and jets. My service manual spec's the following jets for the 115hp:

High speed: 54c
Low speed: starboard - .027; port - .028

pic showing size markings

 

[emdsapmgr]

Re: Need help identifying proper jets

The jets can vary in this V4 engine depending on year/model. It would be extremely helpful if you could post the model number of the engine. It is found on the serial plate tag on the transom mount, or on the round casting plug on the top cylinder. (could be painted over) The picture attached is of that casting plug and clearly shows the model number. Actual jets sizes vary from year to year, depending on the configuration of the carb body. Best to have them match.

 

[TroyHowell]

Re: Need help identifying proper jets

The casting plug says 392448 rph

 

[will62]

Re: Need help identifying proper jets

That's a remanufactured powerhead. Maybe someone else can give you more info based on the number. Could you do me a favor, and give me the 6 digit numbers stamped on the front of your carbs?

 

[TroyHowell]

Re: Need help identifying proper jets

Carb numbers are 324859

 

[emdsapmgr]

Re: Need help identifying proper jets

Bombardier's part database does not include the carb part number you listed. The immediate part numbers around the number your provided are from the 1979 timeframe. Will has provided a point of reference on a 1979 115 hp engine. It is not unusual for the factory to internally jet each carb differently (in this case the idle jets are different)-to keep the combustion temps even. You will find the original factory parts lists for all these engines on the web at: epc.brp.com. They may be helpful to you as you research your engine. Some of these old lists indicate the part number of the jet, but not always the size. It's important to know just which year carbs you have. Do your carbs have choke plates or not? (OMC eliminated the choke plates in 1980.)

 

[TroyHowell]

Re: Need help identifying proper jets

They do have choke plates, after looking at every diagram available on the web I have a good idea the carbs are 1978 based on the manual choke arm. The manual choke arm appears to be unique on the 78, so I'm going with that and have already ordered the 54C jets as Will indicated were the correct ones. In addition to Will's input, I also verified this through my manual and hope for the best. As for the low speed jets, I'll leave those for the next project time because it does seem to idle fair. I'm still interested in finding the exact year of my motor and will continue to search for clues, my father in law must be getting a good laugh out of watching me process through this problem. I'll post the results of my jetting issue once they come in and I can get it out to the lake again.

 

[emdsapmgr]

Re: Need help identifying proper jets

.054C is probably a good bet. Looks like both the 78 and 79 115's used the same high speed jets and they have similar manual choke levers on the port side of the top carb.