# A Few Jet Questions



## gajet31 (Oct 11, 2010)

I have recently purchased a 50 hp powerhead jet on a jon boat. I have gotten used to the controls, but I have some questions/comments. The first thing I have noticed is the necessity of deep water to get on plane. I have gunned my motor to get on plane in 3 ft of water, and I still suck sand/mud/gravel into my intake. Any tips or suggestions on this topic? This is connected to my next problem, and it is really annoying. EVERY time I take out my boat, I end up clogging the tell tale (pisser). I fish mostly rock/sandy river, and it never fails, I look back and see only a few drops coming out of the hole, and that is when Im running wide open. I end up having to use a long piece of metal tubing to wiggle all the sand/rocks out of the hose. Sometime, when it is worse, I have to remove the clip and take the hose out, then fling it around until it is cleared. Does anyone else have this problem? I was trying to design a better way of letting the water exit, such as a larger diameter tube... But that would require new connectors, and a larger hole in the cowling. Other than these issues I am loving my jet. Lets hear yalls opinion on the subject.


----------



## Ranchero50 (Oct 11, 2010)

Get some trimmer string, it works well for cleaning the tell tale out without the worry of poking a hole in it or the thermostat. 

How is your boat trimmed / loaded down? Seems that if you arwe digging so hard that it needs a lot of weight up front, or the motor trim adjusted in further.

Some pics may help as well.

Jamie


----------



## crazymanme2 (Oct 11, 2010)

Don't want to change the size of hose that your water comes out of.If you make it bigger you will lower the water presure used to cool your motor.It is that size for a reason.


----------



## gajet31 (Oct 11, 2010)

I always try to distribute the weight in my boat equally. I usually have my partner and the gear positioned towards the front, which helps me to get on plane quicker. When I take off, should I have the motor trimmed down all the way? That is the way I have been doing it in the past. I trim it all the way down, and once my boat lifts on to plane, I trim it up until I hear a slight amount of cavitation. Which for me, sound like the motor is skipping/jumping. Then I trim it back down a hair until I no longer hear it, and I leave it there. As I come off of plane, I usually lift my motor up, so that when my boat lowers back into the water, the foot is not going to touch bottom. Does this sound right? 

A little background, my boat is a Grizzly 1648, with a 50 hp mercury jet. The beauty of my boat is how light it is. I usually only have one partner, a small amount of gear, one cooler. I have 2 batteries, one is up front, a 10 gallon gas tank, and then the motor. SO... the motor is plenty for my light boat. I have estimated that it will run around 28 mph with the aforementioned setup. 28 mph is plenty fast for me. I have noticed that my boat slides more than my friends jets. A slight jerk to the steering wheel will send my boat on a 90 degree slide, which is quite dangerous. I try to limit this by planning my turns accordingly.


----------



## fender66 (Oct 11, 2010)

Wow....I was just going to ask for more info on your rig and there it is. My first rig was a 1648 with a 40hp Yamaha jet. It would come up to plane pretty easily in a foot of water or even a little less maybe. This is a heavy gauge all welded boat too that I added aluminum floor, casting decks front/rear and live-well. I carry 3 batteries and 2 gas tanks. I won't say it planed quickly, but it still would do it without the issues that you are having.

Check your impeller to make sure it's sharp. It won't make a huge difference, but it does help. While in there, make sure there isn't anything blocking your turbine or outlet nozzle. You might need to re-align your forward/neutral/reverse gate to the outlet nozzle. I can tell when mine needs to be aligned because the steering wheel pulls hard to one side or the other. Also, check the distance of your intake, or foot from the bottom of the boat. It front needs to be level with the back of the boat and the rear about 3/4" lower (if my memory serves me right). Wait...I just remembered you mentioning something that implied you have electric trim? If so, then start with the motor trimmed down, but not all the way. My trimming on my current rig (which is huge) depends on how fast I want to plane. If I'm just cruising slow.....I leave it trimmed down. If I'm "out of the hole" fast....then I trim it higher to start. I have the power to pull up on plane in a handful of seconds though. A little practice with your rig trying different trims will pay off. Once you are up on plane, trim up until the front of the boat starts to bounce a bit. Once that happens...then trim down until it stops. You are trimmed perfectly then. I can also notice a huge difference in my jet trail. It's a lot messier (lots of side spray) when I'm trimmed to low. (hope that makes sense)

Now the cooling flow.....not sure what to recommend here that hasn't been said already. Here is a link that I've found helpful a time or two. Hopefully this will help.


https://www.sschapterpsa.com/ramblings/outboard_jet_maintenance.htm 

Keep us posted. Never hurts to learn more about the jets and how we all solve/resolve our issues.


----------



## gajet31 (Oct 11, 2010)

After further reading, I have decided to take apart the jet unit and learn the inner workings of my jet tomorrow. I do not believe anything is wrong, but I think it will help me to understanding the process of the jet. I am going to remove the intake guard, then take out the impeller, and check my shims and spacing. This should be exciting. 

I do have one more question. I know that jets use an impeller to move the boat, but prop motors also have an impeller that sucks in water to cool the motor. Do jets have 2 impellers?? That would be one to propel the boat, and another to cool the motor, or does the main one serve both functions.

I will post an update about my project tomorrow night.


----------



## fender66 (Oct 11, 2010)

gajet31 said:


> After further reading, I have decided to take apart the jet unit and learn the inner workings of my jet tomorrow. I do not believe anything is wrong, but I think it will help me to understanding the process of the jet. I am going to remove the intake guard, then take out the impeller, and check my shims and spacing. This should be exciting.
> 
> I do have one more question. I know that jets use an impeller to move the boat, but prop motors also have an impeller that sucks in water to cool the motor. Do jets have 2 impellers?? That would be one to propel the boat, and another to cool the motor, or does the main one serve both functions.
> 
> I will post an update about my project tomorrow night.



Ahh....the jet only has one impeller. The Water pump sucks water into it and directs that to the engine to cool it. The impeller that forces water through the jet is totally separate item than the water pump. However.....they both are turned with the engine speed on the same spindle. Your Water pump will sit on top of the impeller housing and bearings. While you are in there....make sure your bearings are good too. It would be a shame to miss that if you are already in there.

There are also some bolts that hold the housing/bearings/etc to the motor shaft....on Merc jets, these are known to loosen sometimes. Make sure you have those tightened before you finish the re-assembly. Do a search for a topic in this section posted by S&MFish (I believe) on this subject. He had links explaining it. If you can't find it..let me know...I'll help.


----------



## Ranchero50 (Oct 12, 2010)

https://www.outboardjets.com/index.php


----------



## gajet31 (Oct 12, 2010)

Well... I started my project today. My first step was taking off the intake, this went smoothly. I was able to pull it off and then I was looking at the impeller. I unfolded the tabs on the last washer, and took off the impeller. On the bottom of the impeller was a metal shield, a rubber washer, and 4 meat washers (shims). I removed these and was able to pull off the impeller. It was in good shape. Above the impeller were 2 more washers. The hole (center) of the impeller had a plastic sleeve, and a shim. 

So far my project was going great. There was no dirt/debris, and everything was in good shape. I was now looking at this

https://www.snyderboats.com/30min_03.jpg

I had read on the previous posting to check and make sure the 4 inner bolts, and 4 exterior bolts were tight. I put the wrench on this first one and disaster struck. I broke the bolt about an 1/8'' from the bolt head. I decided at that point that I should not mess with the others. The broken half fell out, along with the washer, but the sheared off half stayed up in the motor. I am now stuck and do not know what to do. Nowhere in the instructions does it talk about further removing the bolts, and I dont want to do anything else to break it further. One thing I noticed, there were 4 inner bolts, yet there were 6 holes. 

SOOOO, I am not sure of my next move. Should I leave it the way it is? I could forget about it... but I am sure that over time the broken half will fall out and could wreak havok on the rest of the system. I need some input. Other than this current and major mishap, the rest of the breakdown went good. I am confused because according to what I have read, there should be 8 washers total, yet mine only had 6. But the distance between my impeller and the cover is right at 1/32'' so I feel like I should leave it this way. Anybody else encounter a similar situation. If I don't gather anything on here, I will call Outboard Jets and see what they recommend.


----------



## fender66 (Oct 12, 2010)

Okay...unfortunately, I think you need to find a way to back out the broken bolt without messing up the threads. You will need to have that bolt tight to be safe on the water. It could cause a lot of other problems like bearing wear if you don't. I wish that hadn't happened to you as I think it will be a real bear to get that out.

As for the washer/spacers...if your clearance is good (like you say it is) then put it back in the way it came out. The spacers on the top only bring the clearance down tighter and are where they are supposed to be.

Keep us posted....I don't like the broken bolt at all for you. I wish I could offer some advice on how to get that out, but without being there to evaluate....I best not even try. Wish you the best luck with it though.


----------



## S&amp;MFISH (Oct 12, 2010)

gajet- My ? is...Which bolt was it that broke exactly? If it was one that holds the bearing housing on,I think that you should be able to take the rest of the bolts out and remove the housing to get at the broken one. Someone correct me if I'm wrong,as I've never actually had to do this procedure before.


----------



## fender66 (Oct 12, 2010)

S&MFISH said:


> gajet- My ? is...Which bolt was it that broke exactly? If it was one that holds the bearing housing on,I think that you should be able to take the rest of the bolts out and remove the housing to get at the broken one. Someone correct me if I'm wrong,as I've never actually had to do this procedure before.



I was trying to remember that too, but I can't. Guess it's old age at 44. Sorry.


----------



## gajet31 (Oct 12, 2010)

The broken bolt is on the inside... Its hard for me to explain over the computer. There are 4 on the outside, and then 4 more on the inside. If you look at the following picture, it is the one of the 4 labeled "D". To be exact it is the top left of "D". It would be possible to take out the remaining bolts, but I do not know if I up to the job.... Everything in there is new to me, and I don't want to further mess it up. I called Outboard Jets tonight but got no answer, so I will see what they say.

https://www.snyderboats.com/30min_03.jpg

I am shocked the bolt broke, and disappointed. I barely tightened it, just to make sure it was snug, and I heard it crack. You would think it would be strong enough.


----------



## gajet31 (Oct 13, 2010)

Well, good news! I just got off the phone with Dick at outboard jets. He assured me that the bolt breaking was not a life threatening injury to my motor. He told me that I should be able to use the motor until I find the time to break it down again. When I do go in to replace the bolt, he showed me a link on the website which shows a full parts diagram to the entire jet. I will be able to take everything out, and then replace the bolt. He said it should not be too hard. The good news is that when I do this, I will have fully disassembled the jet and will know everything possible about it. So I am going to forget about the problem for now, and address it in the colder winter months. Thanks for everyones input and help.


----------



## fender66 (Oct 13, 2010)

Well, he has more experience than I do, so that's great news. Now go catch some fish.


----------



## S&amp;MFISH (Oct 13, 2010)

gajet; When you do the repair,take some pics of the procedure and post them up if you could.It could be some very valuable info we all could use. Thanks man.


----------



## fender66 (Oct 13, 2010)

S&MFISH said:


> gajet; When you do the repair,take some pics of the procedure and post them up if you could.It could be some very valuable info we all could use. Thanks man.



+1


----------



## Codeman (Oct 15, 2010)

First thing I would do is take the entire pump off the motor, that will enable you to turn it upside down and have a much easier time working on it. Those bolts are stainless, making them a bit softer, ask me how I know. I didn't twist one of those off but there is half of one of the shoe bolts in the pump. LOL I am the king of over tightening. I'm guessing if you remove the rest of them you might have enough to get a hold of and screw it out with vice grips or something. Then when replacing, use a torque wrench.


----------



## Ranchero50 (Oct 15, 2010)

Stainless bolts vs. aluminum usually equals some corrosion. Take some heat to the bolt before taking the rest out, they may even be locktighted (which the heat will break down at around 250` if memory serves). For the impellor, take your spark plugs out and shim it as tight as you can without locking up the engine. Tighter clearance equals better performance. Of course take a file to the impellor edges and get them sharper as well.

Jamie


----------

