94 mariner 60hp Short shaft

[ferdthe4]

So I've been trying to use the search function and find out as much as I can before posting, but I haven't found a whole lot. So that tells me there probably isn't a whole lot I can do with this engine performance wise. I'm just curious still if there is much or or not. I know it's a blind bore so that rules out any head milling or block decking for a bit more compression. If I rebuilt it are there any higher compression pistons that could be put in. Do anything other power heads fit on my mid section? I'm asking cause I got a 94 mariner 60hp short shaft tiller for a reasonable price and am trying to find a jet lower to put on it so I'm just trying to see if there is anything I can do to get a few more ponies out of it to help with the jets power loss.

I know the advantages/disadvantages of a jet for me the advantages outweigh the disadvantages. Shallow rivers riddled with logs, stumps, and gravel bars that I'm in for the most part make it dangerous for prop lowers. So I'm also searching for a jet lower as well but that's a different story. Any tips or advice on this motor would be nice and is appreciated been a longtime browser first time poster. Have gotten lots of good info on here before from reading and appreciate it.

[ferdthe4]

Also meant to mention it is still using the oil injection and seems to run fine with it. Is it pretty reliable on these or should I do away with it for safety?

[Lil' Blue Rude]

Check out tinboats dot net there's a outboard jet sections in the forum. You can make your own exhaust tuner and you can have the reed plate ported and add fiber reeds to wake these motor up a little bit more if it's the 59 cube 3 cylinder. Put a 3 blade 6 7/8" stainless impeller in it. Stainless are a lot tougher then the aluminum ones and they're normally 1mph faster on top end. What size boat are you planning on putting it on?

[ferdthe4]

I've been on the tinboats before reading haven't ever registered might have to and see if I can't have any luck finding a jet foot on there trying to avoid the cost of a brand new one. I believe it's a 59 cubic inch one not real sure how do you tell I haven't been much of a merc man. Only got this one cause short shaft tiller engines above 25hp are hard to come by anymore and this one was a ok price some what close to me that I picked up. It's going on a older excel hull 1554 so 15ft long 54" inch bottom. It's a mod v so the front is point with a little v going to smooth flat bottom. I currently have a 40hp 3cyl carbed nissan tiller on it with a prop it is about perfect for it but I got the 60 as I figured the 40 would be dog on it if I switched it to a jet. I understand switching to a jet I will have to build my transom maybe I'm hoping that my jack plate a full height will be able to get the jet foot at the height it needs to be and if I ever wanted to run the prop again I could switch the lower out. It's a pretty heavy hull for the size it's a .125 bottom and sides full length stringers with full floor so it's a tank I like it.

I was looking for reeds any suggestions boysen ones or what? Boysens were about all I found beside stock replacements maybe I didn't know what to search for? Anyone have pictures of ported reed plates or modified exhaust tuners? Is the reed plate porting as simple as just smoothing out casting marks and any area that seems like it would hinder air/fuel flow?

[ferdthe4]

It is 3cyl blind bore power head if that helps at all. If been trying to search for exhaust tuner modifications on these but have found little info on it just looking for some advice on it never messed with the tuner on a outboard before same with the reed cage porting any advice or info on what is best to do would be appreciated. The only performance reeds I have been able to find are the boyesen power reeds. Do the reeds make that much of a difference, are they worth the cost? I'm just curious if it's worth it all to mess around with this engine some, or if it's just pointless/worthless being a blind bore bore engine (can't shave the head). I figure with a jet it should perform better than if I switch my current nissan to a jet since the jet pump for the mariner uses a larger impeller and it has pretty good displacement advantage over the nissan. If I can ever find a jet for it I did plan on a stainless impeller, but I gotta hunt down a pump first been searching and calling around a lot trying to find one no luck yet.

If I had it my way I would have much rather had a omc 3cyl 60-70hp but those are really hard to find with a tiller the ones I was able to find have been quiet expensive for wore out 20 plus year old outboards. Oh well beggars can't be choosers I suppose.