New guy here with new boat and questions.

[Mule Laker]

Hello,

I'm new here and just purchased a 2007 Glastron GT185 with the 3.0l. We're going to use it for general boating on a small, 600 acre lake. It's a beautiful boat although one side is beat from a dock. The interior is like new however. There's lots to love here but of course I have a few concerns.

I'm coming from a 1991 17' Larson with a 115 Merc and I'm a bit disappointed in the Glastron's acceleration in comparison. It's weird, the new boat planes almost instantly but feels dog slow all the while.

First, in wide open runs across the lake with two adults and a half tank of gas, my maximum rpm was 2400 at an actual 40mph. That's full throttle on a calm lake for a half mile. It does 30mph at an indicated 2000 rpm. Can this be right? I was told I should max out at around 4500 rpm. It came with the standard 3 blade, 21 pitch prop but it was beat up so I put a new Solas 4 blade, 19 on it. Not much different in rpm with either.

 

[Don S]

Re: New guy here with new boat and questions.

You have tachometer problems. No way are you going to go 40 mph at 2400 rpm. You probably wouldn't even be on plane at 2400.

 

[dingdongs]

Re: New guy here with new boat and questions.

welcome to the forum.nice boat and as stated your revs should be uptp 4500 or thereabouts.the speed is about correct but your rev counter is incorrect.40 mph is about the correct top speed but there may be a setting switch on the back of the rev counter that has been set for a 6 or 8 cylinder vessel.failing removing the counter and resetting there maybe a prob with the rev counter and will require replacing.

 

[Mule Laker]

Re: New guy here with new boat and questions.

No way are you going to go 40 mph at 2400 rpm.

Ya, wouldn't that be awesome. I knew something wasn't right. Hmm, I wonder how accurate my idle setting is then?

Crap, so I can't even figure out where I'm at with my prop. No worries, it's going into the shop for winterization so they could check that out too.

 

[HT32BSX115]

Re: New guy here with new boat and questions.

Hmm, I wonder how accurate my idle setting is then?

It's NOT. You MUST have an accurate tachometer to determine WOT RPM (+ drive ratio) and speed to determine if you're propped correctly.

Wrong idle (too high) RPM can damge your drive......A WOT RPM that's too low can damage the engine.


Regards,


Rick

 

[BRG25]

Re: New guy here with new boat and questions.

Sounds like his Tach is the problem. 40 mph is pretty good for an 18 foot boat with a 3.0. If your idle was off, you would know it because it would either stall if too low, or be difficult to get into gear and make a noticeable bang.

 

[QC]

Re: New guy here with new boat and questions.

Agree with all of the tach comments. Check the back of the tach for a 4, 6 and 8 cyl switch. Sounds like it is reading half which tells me maybe it is set to 8 Very common issue.

 

[Mule Laker]

Re: New guy here with new boat and questions.

Agree with all of the tach comments. Check the back of the tach for a 4, 6 and 8 cyl switch. Sounds like it is reading half which tells me maybe it is set to 8 Very common issue.

Okay, just got the boat out of storage. No where near water yet but hopefully soon.

I just checked the switch on the back of the tacho. It's clearly marked and to my surprise it's in 4 cyl, position 1. Crap.

 

[Chef Shawn]

Re: New guy here with new boat and questions.

I am a novice when it comes to props, but my 3.0l (and my boat is a foot shorter than yours), I don't even reach plane until 3000 and max at 4200 at @ 35 mph. Follow the advice of the smart ones, your tach is way off

 

[Mule Laker]

Re: New guy here with new boat and questions.

Hmmm. Maybe the whole tach is bad then. But it's strange that it seem s accurate at idle.

 

[achris]

Re: New guy here with new boat and questions.

Get a proper calibrated 'shop' tacho and do the run across the lake again. Measure the speed with a GPS, not the dash mounted speedo...

Chris.......

 

[Mule Laker]

Re: New guy here with new boat and questions.

Update.

When I was under the dash last week I turned the engine selector all around and left it on 4 cyl. Well I finally got out on the water and to my surprise the tachometer is working. It showed 4600rpm at a gps read 37mph. This problem also affected the reading at idle. After starting the engine I waited a couple of minutes for the idle to come down and it never did. It was set at about 1100 so that was adjusted as well. Now I can choose a prop!

Thanks guys!