Slow boat

[MBJJ2369]

Hello all,

I am new to the forums and really not sure how all this works, so if I do something wrong I apologize.

I have a 1988 Blue Fin with a 1988 50 HP Force. I just bought the boat last year and didn't get to take it out or tinker with it much. The first trip out, the top end speed was 5 MPH. I took it to the shop and was told it could be several things and it would be a replace parts until it was fixed. I replaced the coils, wires and spark plugs and got it up to 15 MPH, but it would not plane out no matter how I trimmed it. Should this boat run faster? Will a faulty stator or trigger cause it not to reach top speed? Any help or suggestions would be helpful.

 

[jbcurt00]

What Blue Fin? How long?

An 18ftr w a 50 will be a slug

16ft it wont be fast, but ought to plane if its not holding water below deck

A 14-15ftr should be fairly easily planed w a 50hp

Get a tach to record/report RPMs at WOT, even if thats only 15mph.

What prop? # of blades, pitch and diameter?

 

[MBJJ2369]

Its 16ft, only a little water came out the last time I pulled the drain plug after being on the water for 6 hours.. It has a 3 blade prop, boat is in storage so I can't say what the pitch is. I will try to get by there tomorrow to find out. Not sure what WOT means. Boat has no tach, how can I measure RPMs?

 

[jerryjerry05]

WOT= wide open throttle.
​They sell an item called a tiny tach or something like that.
​I bought one on e-bay or was it amazon for under $15
​It gets hooked to the top coil wire and gives a reading of the rpm's.

Does the motor rev up when your going or just run slow?
If it revs up and doesn't go anywhere?? it could be a bad hub in your prop?
​Remove the prop, and mark a line across the rubber hub.
Reinstall and go for a ride.Running at full throttle.
Then check the hub.
The 88 came with 2 different ignition systems.
One had points and the other a CDI or powerpack system called a Prestolite system..
Need to know what you have?

You can't add pictures until you have 5 posts.
​You can add pics using a photo sharing site like photo bucket or something like that.

​But before that?? do a compression test, then a spark test.
​I know you said you replaced the coils, the coils can go bad but not usually.
​The trigger leads can break(Prestolite) under the shrink wrap and cause a no fire situation.

​The tank?? built in or the 6 gal. portable?
Built in: make sure the vent line is open.

​But do the compression and spark check FIRST!!!

Oh yea WELCOME!

 

[MBJJ2369]

Thanks for the welcome

The tank is a 6 gal. portable and I have just ordered a tiny tach and compression tester. . They should hopefully be in soon. As soon as they do, I will test the motor and see where I stand. Going to have to wait a bit to test the prop, unless I can achieve the same from running the motor in a barrel. Here is a picture of the coil.

 

[jerryjerry05]

Nope gotta run it in the water.(unless you have a HUGE tank and proper test wheel)
​You have the electronic ignition and no points.

Let us know when you get the comp tester.

 

[MBJJ2369]

I know it has been a while, but I have finally found the time and good enough weather to test the compression. The top cylinder was 120 and 122. I found another prop and weather permitting will take the boat out tomorrow. Will let yall know how it goes.

 

[MBJJ2369]

Took the boat out today. With the new prop on the boat I got it up to 26 mph. Not sure if this is as fast as it should run but I am happy with it.

 

[jerryjerry05]

Remember it's only a 50!!!
You have a tach?
​What kind of load are you carrying ?
​Some think that 2-3fat people(me and my brother) and 2 dogs and 2 cases of beer and bait and the neighbor kid and the boat should run just as fast??
​6gal. gas 1 person and a cooler then see how fast?
What is the top rpm's at wide open?