GTR 37 EFI on 18x60 go devil hull.

Speeds tested with 2 people (130 each) 12 gallons of gas, battery, ice chest, fishing gear.
Deep rough water (open lake): 25-26mph
Deep calm water (river): steady 27mph bumped 28 one time.

Tested with 3 people and 12 gallons of gas with river current:
Upriver: 25-26 mph
Downriver.steady 28 bumped 29 once

Loaded down heavy roughly 1000 lbs (6 full grown adults + dog)
Planed out supriseingly quick all in deep water:
steady 23mph bumped 24 once

Completly empty in the river without current: 30

Empty in river with little/no current
Upriver: steady 30
Down river: Steady 30 hit 31 once

Shallow water: steady 29mph

This motor has far exceeded my expectations, im running up to 5mph faster with the GTR and a light load as compared to the GD completely empty. This thing also blew my mind in vegetation, didnt even struggle compared to the GD...and i added my MM exhaust and its got alot more grunt to it now, the throttle is extremely touchy

Link to review on same hull when i had the GDSD on it to compare numbers.
viewtopic.php?f=5&t=53788

Pics and video

http://youtu.be/_GGTgYvfuC4

Those are good speeds. Where'd you end up putting the trim pin?

Its in the 2nd pin from the top. Bout to drop it down 1 more an see what happens. Called gator tail an they said that might help get rid of some tiller touque. At wide open it makes a right turn as easy as an outboard does but its got quite a bit of push on a left turn..not sure what i can do to help that i tried moving weight around already.

your initial assessment of how the engine itself ran?

nice pics and video!

Thanks for posting honest speeds. Hard to find that on here

excellent! If my 37GD does that or close I'll be a happy camper.

That center engine cover does look kinda goofy though I know it's to hide electronics etc... Looks like it's got a big ass forehead hahaha

I love how it ran. Fired right up and had a smooth idle at 850 RPM's and at WOT it was running 4500 RPMS. I do need to ge my Marshmellow exhaust on it though that POS stock exhaust has a horrible rattle to it..and the throttle response is amazing
Does that sound right for WOT? Also has a lot of tiller torque going to a left turn, already tried weight adjustments and not much luck. Any advice?

Trim down a little maybe. Probably has something to do with the tiller torque.


Sent from my beeper

I had to move mine off center a touch to get most of the torque out - RPMs sound OK fir first run, mine did only about 4000 at first but now it hits the rev limiters no sweat

Take your time and make small adjustments until you get it figured out. Before long you will have it perfect. AKA runs a GTR on an 1860 boat like yours and he likes it

I'll mess with it alittle more tomorrow if rain aint to bad. I moved the pin down 1 hole like GT said. When i got it loaded up i shook the motor for some reason and theres a sloshing water noise coming from the back of the motor..pulled the clutch cover off but no water? Any ideas?

I pulled the greese screw at the bottom but nothing came out.i figured if there was water any higher than that then surely some would come out down there?

There's seals on the shaft, so it wouldn't necessarily make it to the bleed screw. Did you throw some water up on the reverse cover while you were running it.

No water in the belt housing. I listened to it alittle closer just now and it sounds like it may be the oil in the transmission..not positive though. I pulled the clutch cover off and shined a light down there and it looked dry.

Is GT selling those port side wire covers?

Im not to sure they might idk.
So what exactly is the purpose of the trim pin?

If you look at the motor, it tilts from two different positions, the top one at the transom bracket which is caused by the lower unit flipping up. The bottom one is pivoted about by the trim unit and the slide up top.

If you move the trim pin up and use the trim unit to get the shaft at the same angle, you're effectively moving the motor up on the transom and back on the boat. The opposite is true for the lower holes, but you run out of up-trim.

Yeah once i got back and looked at it alittle more I figured thats what it might be

The Briggs EFI does not have an O2 sensor if I'm not mistaken.

the first Briggs EFI I saw late last summer had an O2 - I haven't seen an O2 sensor in any since. The bung you weld in is standard size, I think MAC is offering it on his. I think I am the only guy running an O2 on PD EFI.


http://www.amazon.com/Vibrant-1194A-Sta ... ds=o2+bung

Thanks for the review. I didn't realize there could be balance issues with the motor and having too much torque one way or another. Is it pretty common to have to move the motor around until you work out all the kinks?

when i had my first gtr on a 1848 gdsd hull i had to shit motor 2" to the left(away from driver) to get rid all tiller torque. dont add thru hull bolts just use clamps bring tools needed to launch to slide it over some (wrench for clamps, hammer, piece of wood). move a hair, go run once perfected drill holes and add thru hull bolts.

also briggs efi open loop it doesnt have o2 sensor

O2 sensor would be in the exhaust where the two cylinders commingle.

O2 would be in muffler

in a closed loop efi it would be in the exhaust but the stock briggs wont have it. and trust me you gonna want to move it over. it will tire your arm out holding it over on longer runs. i fought the same issue you are having back in the day

You can use any exhaust for a horizontal shaft engine. The Briggs EFI does not have an O2 sensor. If you're asked, tell them you DO NOT need an O2 sensor bung. I was surprised by this when I took delivery of mine, but it's the same for all of them. The PD EFI/Ecotrons kit is the only one with an O2 sensor, and even that one is optional.

o2 sensor.jpg

Thanks for pointing that one out. So if the motor is wanting to push into me (right turn) which way does the motor need to be moved?

away from you. so to the opposite of the boat. go 2" and run it see how it does.