2000 Glastron SX-195 Backfiring, high RPMs but not matched speed?

Joined
Sep 13, 2018
Messages
17
Hi.. I am bran new to this forum.. I just purchased this boat at auction and found that it has been sitting for several years.. I filled with gas and it started right up.. Took her for a ride today with my wife and everything went smoothly.. except that it felt like the prop was sucking air... RPMs went to 5000 with a reported speed of 30MPH? it actually felt slower than this.. I had a backfire upon acceleration and intermittently as we rode.. One thing to note.. the PROP was a 14.75 x 19.. and it has one of the fins slightly bent(1/8 - 3/16") in middle of blade.. Could this cause the sucking air feeling and lack of speed?

I have a SS 14.25 x 21... what affect would this have on my ride? It is in great shape....
Also.. do I need a puller to remove the existing PROP?

Thanks in advance..
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Welcome Aboard!

What engine does it have? The SS 21pitch may be too much, but need more info.

As for a needing a prop puller, depends on how well the current prop shaft splines were greased before it sat.
 
Joined
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Thank you..

It has a 4.3 Volvo Penta in it.. the ratio on the drive is 1.79.. When you say that the SS PROP would be too much.. what are you referring to?

Also.. I lost the grease cover on the upper unit today.. (was going to change the fluid.. forgot to tighten bolts) frustrating!! Where do I find one of these creatures.. SX-M drive..
 
Last edited:

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Grease cover on the upper unit? Do you mean the plastic cover shown in the first pic? Or the aluminum cover, held by 4 bolts and has a dipstick in it? The plastic cover is over $200. The Aluminum one? You've got trouble. VP specs are Only a Full Synthetic GL5 gear oil be used. Using other gear oils may result in bearing failure.

I suspect the backfiring is from a leaning out of the carb. Probably a plugged up power circuit. Easy to clean on the 2bbl Holley, just remove the fuel bowl and the metering block and all the passages for the fuel circuits are laying there to see. A few squirts of carb cleaner into the passages in the main body will clean that part.

Where was the out drive trimmed when the rpms went to 5000?
The WOT range of that engine is 4400 - 4800.
A bent blade, can lose its bite/grip on the water quite easily. Looking at the pic, your prop is toast. Replace or repair it

Your trailer looks like the tires are flat, Don't use car/truck tires on it. You also need to recarpet the bunks

I have the same boat, but I have a 5.7 VP in it. A 4.3 should push that boat to the high 40s
 
Joined
Sep 13, 2018
Messages
17
Grease cover on the upper unit? Do you mean the plastic cover shown in the first pic? Or the aluminum cover, held by 4 bolts and has a dipstick in it? The plastic cover is over $200. The Aluminum one? You've got trouble. VP specs are Only a Full Synthetic GL5 gear oil be used. Using other gear oils may result in bearing failure.

I suspect the backfiring is from a leaning out of the carb. Probably a plugged up power circuit. Easy to clean on the 2bbl Holley, just remove the fuel bowl and the metering block and all the passages for the fuel circuits are laying there to see. A few squirts of carb cleaner into the passages in the main body will clean that part.

Where was the out drive trimmed when the rpms went to 5000?
The WOT range of that engine is 4400 - 4800.
A bent blade, can lose its bite/grip on the water quite easily. Looking at the pic, your prop is toast. Replace or repair it

Your trailer looks like the tires are flat, Don't use car/truck tires on it. You also need to recarpet the bunks

I have the same boat, but I have a 5.7 VP in it. A 4.3 should push that boat to the high 40s


I didn't realize it was plastic? yes.. the one with the decal on it.. I have correct oil to put in it..

The trim was all the way down with just my wife and I..

I will replace the bad prop.. but with what? What Prop do you recommend?

Also..This pic was from auction.. after sitting for years.... have new trailer tires on it now.. Plan to carpet bunks soon..
 

89retta

Senior Chief Petty Officer
Joined
Jul 18, 2010
Messages
772
Start with getting the engine running right first. Then move onto the prop. Also have you changed the engine oil ?
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Me:"The SS 21pitch may be too much, but need more info"

I was referring to the pitch. A 21 may be too much, but with that engine and drive ratio it may work ok. That is why I asked about the engine, as a 3.0l would probably not be able to swing a stainless 21p on that boat.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
What you are saying could be caused by a few things, but more than likely might be water in the fuel
 
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