Wanted to buy 40hp jet

[Flyguide7]

Guys,

I am looking for a clean 40hp jet electric start outboard. Please send me a PM if you have one for sale.   I have a 1984 25hp mercury jet for sale because it is too small for my boat. 

Thanks,

Ed

[BilletHead]

        Ed,

  Hope you find the motor you want but be very careful in the quest you undertaking. If you are going to put it on your 1448 it will be heavy. I had a 1648 riveted just like you have and it was rated for a 35 max. I put on a 40 hp. prop. It would run like a banshee but started developing a crack or two in the back corners. The guy who bought it off me got it welded and it is still going to this day. The recommendations for your rig says 25hp. max. I see you are a super good fisherman and know what you are doing but just cannot not say what I think. Not being a turd just concerned. My 1648 would take on water over the back if you stopped too fast or got on a lake with some waves. I like what you did making your deck,

  BilletHead

[fishinwrench]

Not to squish your project but have you checked the impeller leading edge and shimming, and made sure that your throttle plates and trigger coils are moving fully into the WOT position? 

I know of several 25 jets on 16' Jon's that get up and scoot just fine.   You may just not be getting all out of your little 25 that you are supposed to be getting.  Just a thought.

A buddy recently had a 30 jet that had lost its balls, but a little impeller tuning woke it right up.  

[Flyguide7]

10 minutes ago, fishinwrench said:

Not to squish your project but have you checked the impeller leading edge and shimming, and made sure that your throttle plates and trigger coils are moving fully into the WOT position? 

I know of several 25 jets on 16' Jon's that get up and scoot just fine.   You may just not be getting all out of your little 25 that you are supposed to be getting.  Just a thought.

A buddy recently had a 30 jet that had lost its balls, but a little impeller tuning woke it right up.  

Thanks! I will check that out. The guy that sold it to me said he just had the pump rebuilt at Big River Marine. 

 

6 hours ago, BilletHead said:

        Ed,

  Hope you find the motor you want but be very careful in the quest you undertaking. If you are going to put it on your 1448 it will be heavy. I had a 1648 riveted just like you have and it was rated for a 35 max. I put on a 40 hp. prop. It would run like a banshee but started developing a crack or two in the back corners. The guy who bought it off me got it welded and it is still going to this day. The recommendations for your rig says 25hp. max. I see you are a super good fisherman and know what you are doing but just cannot not say what I think. Not being a turd just concerned. My 1648 would take on water over the back if you stopped too fast or got on a lake with some waves. I like what you did making your deck,

  BilletHead

Thanks for the advise! I appreciate it.

[grizwilson]

If the pump has been recently rebuilt it is likely fine.  Each year I sharpen/straighten the grates, sharpen the impeller, check the liner and adjust the shims to 1/32 of an inch (.03125) (a heavy piece of paper).  I also take EVERYTHING out of the boat and reload just what is needed, things seem to accumulate.  Distribution can also be key.  Not sure what size boat you are pushing, I run a 20x42 glass river boat with a merc 25, it is not fast but does fine.  That said those Tohatsu 25 jet drives are sweet, but pricey

[Flyguide7]

Well this morning I checked the throttle travel and the throttle opens completely. How do I check the trigger coils?  I took the impeller housing off and this is what I found.  The edges look to be pretty blunt (.091") The impeller housing looks pretty chewed up. What do you use for shims and where do you get them?

Thanks for all the helpful comments guys I appreciate all of your feedback.

[grizwilson]

you use the shims on the motor, move from bottom of impeller to top to reduce clearance, your impeller needs some filing, I use a hand file as afraid of ruining impeller, Pros like Wrench can likely use power tools. hard to tell on cup wear from photo, see one pretty big nic. I would try sharpen shim on impeller, your grates look pretty good from what I see. Wrench is much more knowledgeable than I. 

[BilletHead]

Looks like you are on your way to a possible solution. Getting on plane, maybe not so fast but I have found the slower I go the better the fishing and catching at times. 

  BilletHead

[fishinwrench]

Oh hell yeah.   Definitely Mr. Impeller needs to be introduced to Mr. Angle grinder.  

When reinstalling just relocate shims like Griz says until the impeller starts scraping the cup, then back off one shim.  

At the hub of the impeller you can see how much material is missing from the leading edge.  When it gets much over 1/4" (let's say 3/8") then it's time to think about ordering a new impeller.  

The trigger coil is what rotates under the flywheel when the throttle is moved, it advances your ignition timing.  Be sure that at full throttle the trigger rotates fully against its stop.  

See, that "rebuild" wasn't a rebuild, was it?  😀

[Flyguide7]

So I think this is an improvement