# What shaft length jet would work best on my Lowe 1652 VT?



## JL8Jeff (Nov 11, 2013)

The boat currently has an Evinrude 40 hp prop (20" shaft) and I want to switch to a jet. The options are to convert the existing engine to a jet and probably need to lift it at the transom with a bracket or jack plate. I could buy a used jet outboard so that would give me the option of runnign a 15" jet or 20" jet. I'm finding engines of each length in the area so what would be the preference? Obviously the short shaft limits what boats you could use the engine on in the future if I were to sell the boat and keep the engine, but I'm not worried about that. I'm thinking the 15" shaft might work better since it wouldn't need to be lifted. Also, can you run a jackplate that sets the engine back 3-5" or will that mess up the location of the jet intake too far behind the boat? Here's what the boat looks like now.


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## BigTerp (Nov 13, 2013)

I would suggest you go with the short shaft which will keep you from having to raise your transom much, if at all. My transom measures 16" and I had to raise it 4-3/4" to fit a short shaft '94 Johnson 50/35. I'm not sure if all short shaft jets measure the same, so I'd take a tape measure with you if your considering buying one to make sure you don't end up with one too short. Measure your transom as well from top to bottom. Mine is considered a 15" but actually measures 16".

I considered a jack plate but ended up going with a simple riser made out of aluminum sheet and angle. You can see it in my build thread. We got lucky and it ending up setting the motor perfect. Zero cavitation, no splashback and it runs great. I shot for getting the front of the jet even even with the bottom of my transom, as suggested by others on here, and it was dead on. I don't like the idea of the extra torque the set back of a jack plate puts on the transom. Also not sure how it would effect how the jet runs.

I just noticed this, but does your hull have a tunnel, or is that a splash plate? If it has a tunnel a jet would be really nice on it!!


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## JL8Jeff (Nov 24, 2013)

Yes, the boat has the tunnel with a bit of a splash plate built in. I just picked up a mid 90's Mercury 60/45 short shaft jet for less than the cost of the jet conversion to my Evinrude 40 so the fun is about to begin. The motor was hit by a tree that came down last year during Sandy so the hood has some damage and the throttle arm broke off. It came with a new starter installed and he had the replacement throttle arm parts as well. It has the shift cable but the throttle cable snapped off at the engine and the wire harness was cut but I think it should be long enough. No power trim so that wiring isn't needed. I wonder if I can use my OMC controls and just swap the Mercury cable ends so I have them. Unfortunately, it's 25 degrees outside so I won't be doing much with it today (it's in the garage but it's cold out there too).


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## BigTerp (Nov 25, 2013)

Sounds good. Since your hull is tunnelled, I'm guessing you'll have to raise your transom even with a short shaft motor to get your motor at the optimal height. I don't think you'll be able to use your Mercury cables with an OMC controller. For one, the cable ends will be different (not sure if you can swap those out) and I'm also not sure how the wiring would work from an OMC controller to a Mercury motor. There may be some conversion kits or something you could get though. I have a set of Mercury cables that won't work with my '94 Johnson and OMC control box. I hear you on the cold!! I have a set pair of HID converted driving lights I need to install, but we had a high of 26 yesterday and this morning it was 11 degrees. Waiting for a little bit of a warmer day before I tackle that job.


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## JL8Jeff (Nov 27, 2013)

I was measuring it up last night and it does look like the short shaft jet will still need to sit up an inch or 2 for the intake to be postioned behind the tunnel. I wonder if it's worth putting something their to raise the transom a little or will it just trap moisture and lead to potential problems.


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