I just bought my first boat! I hope I am not hurting anything.

[mattallen]

Hello to everyone and thanks in advance about any help given.
I have been reading the forums from before I bought my boat but I still feel like I do not know anything.

I bought my first boat a little over a month ago. I think it is a good starter boat.

It is a 1979 Sea Sprite (fiberglass Tri-hull) with a 1975 70hp Johnson. I bought the boat motor and trailer for $400.

When I bought the boat it had been sitting for about 2 years and I am not sure if it was winterized, and I was not able to test fire the motor.

Here are some things that I have done to the boat after getting it home.

Changed oil in lower unit
Changed spark plugs
removed the old gas from tanks
replaced the gas line and primer bulb
replaced the stereo
Put on a new prop
Replaced the battery
General Clean up of boat(it had moss growing inside the boat)


I want to make sure that I am not causing any damage to my boat.
The first time I put the boat in the water after doing all the above work at WOT I was going 10 mph(not planing) and after a couple of minutes it would get up on a plane and the speed maxed out at 18 MPH.

The engine Idles just fine and sounds like it is running right(so several other people have said).

With suggestion of a friend I put the old prop back on because he thought that could be the reason behind it. (it bought the other prop used and I do not know what the pitch is of either of them)

With the old prop the boat pops up on a plane fast and the speed at WOT is 24MPH.

Currently I have the old prop being rebuilt, and I am wondering if this boat should go faster than 24MPH?

If it is suppose to what could still be wrong with it?
Would it hurt the boat to keep running it the way it is?

 

[Home Cookin']

Re: I just bought my first boat! I hope I am not hurting anything.

I'd like to know the length of the boat but assuming it's a 16, your prop change was a step in the right direction. You might get up to 35 is my guess. Are you using a GPS (reliable) or the speedometer on the boat (not reliable?) You might also improve your speed by trimming the motor.

There are places to check specs for the best prop.

Congratualtions on getting the motor to run. Luckly for you it was probably packed away before ethanol. Smart move getting rid of the old gas. Get a seperator 10m on there ASAP. You're either a great mechanic or a great scavenger!

You can eventually wear out a motor if the prop isn't right, but hey, we're talking about a 40 year old motor that cost $133!

 

[RotaryRacer]

Re: I just bought my first boat! I hope I am not hurting anything.

24mph seems a little slow. However, you didn't mention the length of the boat or the method you used to measure the speed. Also you didn't mention the rpms of the motor at WOT. If the boat has a tach that would be a helpful number to have.

All that being said I would check for waterlogged foam and rot under the floor. I would guess if the boat had moss growing in it, it also was very wet and probably waterlogged. That can add a lot of weight to the boat and cause it to go slow. It can also lead to severe rot in the structure of the boat which could lead to a hull failure.

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

the boat is a 17ft tri-hull. it actually seems to be somewhat of a heavy boat. However the boat doesn't have a tach so I don't know my RPM's.

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

My wife and I plan on doing an over haul to the boat this winter.

we plan on:

Replacing any and all rotten floor boards
replace carpet
re-wire the entire boat
replace speakers

 

[rockyrude]

Re: I just bought my first boat! I hope I am not hurting anything.

In your list of things you've already done, I don't see replace impeller and tear down/clean carbs. Those are probably the two most important things to do to a motor that has sat for two years.

 

[Gary H NC]

Re: I just bought my first boat! I hope I am not hurting anything.

Once the floor is up you will see the stringers and foam,if it has foam..
My bet is its all water logged..

With an outboard that has set that long the impeller needs replaced and the carbs cleaned and new kits put in..

(rockyrude you post faster...lol)

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

I guess this is how new I am to owning a boat. I know what and where the carbs are but I am not exactly sure what the impeller is or what it is for.

 

[rockyrude]

Re: I just bought my first boat! I hope I am not hurting anything.

I guess I missed one item, get an oem manual for the motor it will prove invaluable. The impeller is what keeps cooling water moving through the motor preventing even costlier repairs, it is located in the lower unit. A manual will walk you thru it.

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

ok thanks for the help.
I put a picture of my boat and motor in my signature.
Have a look.

 

[Gary H NC]

Re: I just bought my first boat! I hope I am not hurting anything.

Post the engine model number and i can help you locate the real factory manual.(It should be on the transom bracket)
The impeller change and carb rebuild is not that difficult with the service manual.
All us guys here can help you through it.

 

[ezmobee]

Re: I just bought my first boat! I hope I am not hurting anything.

The guys already give you the most important info so I'll just chime it to tell you that that is indeed a great first boat, with a proven reliable motor that has great parts support. You did very well for $400. That boat will be well worth the effort you put into restoring her.

Assuming the correct prop and a non-waterlogged boat you should be able to hit close 30-35 MPH I would think. As was suggested you definitely want to get a tach to make sure you are able to hit the proper WOT RPM range. A tach will also let you know your charging system is working which is a nice plus. Good luck!

 

[rs2k]

Re: I just bought my first boat! I hope I am not hurting anything.

For comparison, my old 17 foot tri-hull looks very similar to yours. With a tired 100 HP evinrude it does 32 MPH at full throttle and planes very smoothly and almost instantly.

 

[bowman316]

Re: I just bought my first boat! I hope I am not hurting anything.

only change the impeller if there is not a lot of water comming out the **** hole in the back of the motor.

I have a 70 on my 16 ft runabout, and it maxes out at 26 mph.

You need to get a tach to see where your rpm's are.

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

70ESL75 is the model number on my engine.

Also I should state that when I got 24 MPH I had 4 large adults, 1 child, and 2 dogs in the boat(with the old prop back on it). It did plane very fast even with the 2 biggest guys in the front of the boat

 

[rs2k]

Re: I just bought my first boat! I hope I am not hurting anything.

70ESL75 is the model number on my engine.

Also I should state that when I got 24 MPH I had 4 large adults, 1 child, and 2 dogs in the boat(with the old prop back on it). It did plane very fast even with the 2 biggest guys in the front of the boat

That sounds like your getting decent power out of the motor. The new prop is obviously incorrect for that boat and motor.

 

[mattallen]

Re: I just bought my first boat! I hope I am not hurting anything.

I can do some things mechanically but I do not know much about the carbs and boat motors in general. Should I still go through the carbs and stuff before I take it out on the water again? Otherwise I will plan on working on that stuff during winter in a heated garage.

Am I getting decent enough power to run it for the summer with out hurting the engine or should I do all the work right away?

Sorry for all the questions.

 

[ezmobee]

Re: I just bought my first boat! I hope I am not hurting anything.

Buy a tach and hook it up. Take your boat out by yourself or with a light friend and open her up. See what kind of RPM you're getting. If it's under 4000 you should probably do some wrenching or start trying some props. If it's closer to 5000 you're good.

 

[rockyrude]

Re: I just bought my first boat! I hope I am not hurting anything.

Doing the carb work might be able to wait if it's running decent but you need to change the impeller immediately, the last thing you need is for the old one to go south on you in the middle of the lake and fry your motor.

 

[rs2k]

Re: I just bought my first boat! I hope I am not hurting anything.

Doing the carb work might be able to wait if it's running decent but you need to change the impeller immediately, the last thing you need is for the old one to go south on you in the middle of the lake and fry your motor.

I second that motion!