Looking to repower

[taptap]

So I have a 14 38 flat boat that I'm needing to equip with a jet drive. I'm 210 pounds and will normally have my wife or my 2 kids with me I have a early 90s 15 evinrude on it right now and I'm running about 15 to 18 mph with the wife and a fishing load. I was curious as to if the 30 yamaha jet or the 25 mercury jet would be a good option. I would like to go a touch faster but nor required but definitely don't want to go any slower I also have a 15 in transom on this boat. Any help would be much appreciated. I work offshore and the service is choppy at best out here. Also this is my first post so if I've done something wrong thanks for the patience in advance.

 

[Lazzlo]

Can only get motor to throttle up to about half power. Upper plug is fouled more than lower. Both are month old.

 

[Lazzlo]

Sorry for terse post, I keep losing my replies before I can post! 1974 25hp evinrude, ran great then didn’t. Fresh gear oil, plugs , gas, carb clean, thermostat, fuel pump. Will only throttle up half speed. Upper plug fouled more than lower. Came with boat,I’m moving on from this motor

 

[Lazzlo]

Sorry for terse post, I keep losing my replies before I can post! 1974 25hp evinrude, ran great then didn’t. Fresh gear oil, plugs , gas, carb clean, thermostat, fuel pump. Will only throttle up half speed. Upper plug fouled more than lower. Came with boat,I’m moving on from this motor

Thanks to all who helped on my transom height post and Repower post. I can’t diagnose this motor and don’t have local resources to help. Can’t help but wonder what it needs, feels so close…..

 

[LDUBS]

Hi @Lazzlo. Did you intend to post under your previous thread named "Repower". This appears to be a different thread started by Taptap named "Looking to Repower". Might have more continuity if you move your comments to that other thread -- unless I'm all wet.

 

[Lazzlo]

Guess I’m making a few mistakes tonight, sorry!

 

[FuzzyGrub]

So I have a 14 38 flat boat that I'm needing to equip with a jet drive. I'm 210 pounds and will normally have my wife or my 2 kids with me I have a early 90s 15 evinrude on it right now and I'm running about 15 to 18 mph with the wife and a fishing load. I was curious as to if the 30 yamaha jet or the 25 mercury jet would be a good option. I would like to go a touch faster but nor required but definitely don't want to go any slower I also have a 15 in transom on this boat. Any help would be much appreciated. I work offshore and the service is choppy at best out here. Also this is my first post so if I've done something wrong thanks for the patience in advance.

Those jets are very heavy for a 1438 and it sounds like you have it very loaded. It is a narrow boat and is going to be slow to plane. My son's friend had a 1436 with a Merc 2-stroke 25/20, that was hard to plane, even with just himself or two people. You will also need a jackplate or build up the transom 5".

The maker of the jet pumps has some good info on boat selection: BOAT SELECTION I recommend reading and looking at the weight vs horsepower very carefully. While the 1438 will probably be marginal with a jet, you might be much better off looking for a better hull to work with. A 1648/1650/1652 with a 40/30 or 60/40 is probably a much better solution for what you are trying to do.

 

[taptap]

Awesome thanks for the info I have a 1648 flat boat as well with a johnson 48 spl and a jack plate . I've seen that you can do a jet conversion on motors. By any chance are you familiar with jet conversions and if so will it be enough to push my 1648 with the wife and kids. Im not looking for speed records just a good time and ride on some shallow rivers in south louisiana

 

[Still Afloat]

Fuzzygrub is right about the weight. My Mercury F25ELH JET weighs 196 pounds. It’s too much weight for my 1448 without ballast near the bow. I would not even consider installing this motor on a smaller boat.

I bought the above motor from a guy with a Lowe 1648. He was selling it because it was a real dog on a boat that size.

It might be Ok on a 15 ft boat or a wider 14 ft but, I haven’t tried it. If you really a jet boat I suggest a bigger boat and jet.

 

[FuzzyGrub]

Awesome thanks for the info I have a 1648 flat boat as well with a johnson 48 spl and a jack plate . I've seen that you can do a jet conversion on motors. By any chance are you familiar with jet conversions and if so will it be enough to push my 1648 with the wife and kids. Im not looking for speed records just a good time and ride on some shallow rivers in south louisiana

I think it would a better platform than the 1438. That would be about a 33-34HP jet. It looks like they have models for E/J, but would need to contact them for your specific model. Last I knew, you had to order a year ahead of time. No, I have not done the conversion myself. We have a factory yamaha 90/65 on a 1752 tunnel hull. I have looked through the procedures, and they don't seem that hard. You can find them on their website and evaluate if it is within your comfort zone. I will need to remove ours for its first waterpump impeller change next year.

If your hull can take it, a 60/40 jet might be a better option. You do see them come up on the used market, as people upgrade to larger. Might find one that cost the same or less, as a new jet lower. Also want to make sure the Johnson motor is in very good shape/condition.

While there are a few tweaks you can adjust on a jet (height, weight distribution, etc), not as flexible as a prop motor. ie there are allot of prop choices where the jet impeller you are basicly fixed to. The 30% derating is very general. ie I think a 40HP prop will still outperform a 60/40 jet.

I can't help much with La rivers. I envision mud vs gravel, but thats about it. You may what to look into surface drive motors- long/short tails, mud motors, etc.

 

[taptap]

Roger that, I really appreciate the input on all of this there isn't much mud on our rivers mainly sand and gravel.Thanks again though. I'm going to keep the 15 hp on my 14ft and refigure on my 1648 may do a tunnel on it with that 48spl

 

[LDUBS]

Guess I’m making a few mistakes tonight, sorry!

No worries. Not a big deal.