Hello, I've been following this site off and on for a few years.
To start a little about me, my boat and motor.
I'm an avid waterfowl hunter, been running long tails for about 20 years.
My current rig is a 19ft Jon boat with a 35HP long-tail motor. The places I hunt are the shallow backwaters of a large river. The boat is usually heavily loaded.
After 4 years of problems with this 35HP carbed Briggs I decided to upgrade to a 37 EFI.
Through a local shop I ordered a Briggs 61E377-0009. Mud boats is listed as a typical application on several sites.
http://www.brandnewengines.com/61E377-0 ... fgodSSEFcA

The engine arrived and I noticed that it has an O2 sensor. So I called Briggs to find a part number for a muffler with the bung. They called back a short time later and told me that marine engines do not have an O2 sensor and this is not the correct engine for a boat. Still waiting for them to call back with the number for the correct engine.
I also haven't called the shop to see about the possibility of returning this.

So my question is, is there any difference besides the O2 sensor (and I assume EFI program) Can I simply add the bung to my muffler and run this as is? Can it be modified?
Does anyone know the Briggs model number for the correct engine?

61e477-0007-j1 is the engine you need.. You also need to verify the proper crankshaft for the application you are using.

OOOPS!!!

The crank that is listed on the engine I sent was the 1.125"x4" PTO

Thanx MaXXis

My 35 was 613477-2193-G1
I believe 1.125"x4" is correct. and I did get the correct shaft size.

So far I have found out a few difference for one you listed has a larger alternator (20/50A, compared to 20A).
Apparently the EFI for mowers does use an O2 sensor, (that difference is why I discovered it).
The Marine engine governor is set 4750 RPM instead of 4000.

The shop I bought it through is looking into getting the right one (backordered at their normal warehouse).
He's also checking into if this one can be modified. Suggesting we add a bung to the muffler and adjust the governor up if needed. (The 35HP motor had a 20A alternator and never hit 4000 RPM in the water).

Well this is getting to be a real PITA.
Apparently the distributor wants a 20% restocking fee (between $500 and $600) for this engine to be returned (along with return shipping).
They are saying there is no difference (other than 750 RPM) the stainless muffler will bolt right on.

The shop is checking into what Kohler has to offer (different distributor).
Anyone have any other ideas?

I'd make the Local dealer Eat the costs, or have them keep that engine and put it on a mower and order you another one.

I know its a longtail and you will probably not see many more rpm's over 4000, but 4750 and 4000 rpm's is a HUGE difference.

See if the guys at delta will swap you a STOCK ecm that has 4750 programming for yours. They reprogram them anyway for higher limiters on some of their packages and mod the
Stock ecms. Core is a core, no?

Some one sold u the wrong engine. They are two different engines. Coils - programming - charging systems- who told you it would have same performance. And the 02 sensor is not needed. Talk to your dealer and have him talk to zone rep. Most of the time they will wave restock if it is a misunderstanding. You will pay shipping most likely.

So I sat down and compared the parts lists of both engines. Very Similar (including coils).
The Marine version has a larger (20/50A) charging system, the governor and O2 were pretty much it.
I did modify the muffler and shield to accommodate the O2 sensor.
I bought a new key switch and wiring, because it is a little different than what my 35 had. Also leaves my old 35 complete if I wanted to use it. (I believe the marine engine recommended comes with this already).
I installed a tinytach but it appears that I have the wiring to connect a Briggs Tach, which would be a cleaner install but costs significantly more.
Cost wise I saved some (about $350). figuring in wiring, tach and muffler modification.
Availability, I might still be waiting if I ordered the marine engine as the distributor didn't have it in stock and didn't know how long it would take to get one.
I've had it out several times. Temps down to the upper 20s. Starts right up, runs smooth at all speeds, temps and better throttle control.
As far as performance with the boat (a Lowe 1960MT) lightly loaded tops out around 3850 RPM and 15-16 MPH (measured with GPS). with 4 guys, 10 dozen decoys, gear, etc. closer to 3800 RPM and 12-14 MPH (depending on weight distribution).
I never accurately checked the fuel usage on the carbed 35 or this one but I believe this uses significantly less.
So yes, I did buy the wrong engine. But so far I am happy with it.