Were the FSM and O2 sensor improperly diagnosed or did another problem come up? If the cowling was installed and everything started worked properly, it sounds like they’re missing a loose connection, pushed back connection pin or even a chafed wire.

These issues are on new motors?

Padraig,

I got my new stage 4 drive with cyro, polished and drive guardian back from George this spring.
With the goofy season this year, I got it broken in plus 25 hrs.
I think George is great, Hopefully it will last but looking at other options in the event it goes again.

With all of the Merc. Xr ZR bla bla bla problems what's a solid drive for a HTM cat with 700 hp range.

Looking at a surface drive set up from Arneson Ind. but don't know of any other options.

Standard Bravo with an extra or 2 in the back of the truck.

i have to ask : how did you break a prop shaft on an M8?

You may ant to investigate your shaft drive through Twin Disc (which is Arneson drives) as there is a lengthy thread on OSO about major issues people had dealing with Arneson Industries regarding delivery of drives drives and parts. It may be resolved now but throwing it out there for your due diligence.

ASD08 ARNESON SURFACE DRIVE | Twin Disc, Incorporated

That was the issue originally when the motor shut down the first time (was about 75miles offshore in a solid 3-5ft chop around 30mph). Mechanic said the exhaust temp got up to about 1800deg (yes I had the new recall exhaust sprayers in) SO I think that caused a cascade of events and one thing after the other started failing (including chafed wires too), He independently tested fuel flow rates between the rails and one of them was significantly less so the FSM was ordered. And then the other parts were ordered based on codes thrown He put the ECM harness on today which sounds like a nightmare to replace considering how compact that motor is, and plan to splash tomorrow and see how it goes.

Yes this is a "new" 450R, 160ish hours at the time this happened.


--Yea, how did you go through an M8 drive!!! I want to go for a ride when thats fixed lol!

Turbines on a 50ft cat....

Sorry to Gator MD for the derails but to 302 - Nice lead in but what cat is it?

Htm sr-24

I can only imagine being in this boat. Pun intended.

Gator has done much better than I would have in his situation.
Id still be horse due to shouting from the roof tops.

For those bashing/blaming OBs, it’s part of buying the first of the first.
You could write a book on initial production runs of ......., x that should have been held for release until ......., x was corrected.
This applies to OBs, cars, bikes, planes, blenders etc.

When I was a kid I worked for Snap on Tools, repairing air tools.
They released a “new” 1/2” impact (IM 51 I think) that failed out of the box.

We repaired crates of them and also scrapped (as in, new in box to the local salvage yard) crates of them.
Sometimes 20 - 30 per day.
We gear heads couldn’t understand why these experts (quality isn’t expensive, it’s priceless) released this model when they knew it was ****.

The only answer we ever got was, “it was dictated by marketing”.
Corporate decided the black eye from warranty claims wasn’t as painful/$$$ as missing that moment in the market.

As a beat up and scarred sales guy, I can verify that if corporate is making the call, they listen to marketing.

Gator, as an OB guy, stick w/it.
Once through your teething pains, I think you’ll be a happy camper.

Best opf luck sir.

New motors = New money

I meant my last post to be in follow-up to this comment.

New Motors = New Money

Agreed guys. It's always a risk, which I definitely took. But, this is my FIRST boat and during the build the 450R came out- I had to have em! So, here I am while the other 400R boaters are living the dream on the water. Upside is that Mercury is a reputable company, and I am certainly NOT the only person dealing with issues. So, I'm sure they'll come around and make good on their word/warranty.

Meanwhile, my boat was splashed today, after ECM harness was replaced it is still throwing a bunch of codes and dumping tons of fuel with black smoke. Mechanic did a compression test and fortunately all 8 cylinders are holding strong. So he jumped on the phone with mercury and they ordered more parts.......Very defeatist for me today as, I'm not on call this weekend and could've enjoyed the weekend here (since the storms moved west) but, here I am, it is what it is. Fortunately, mercury is honoring warranty, labor, and parts and I am cost free. Nonetheless, I have my brand new boat out of commission. One of these situations like twin sonic pointed to, the motors will eventually be fixed and running hard and I'll forget about this. Meanwhile, I'll hope the boat is ready for Tampa!

When I worked for a company that supplied the OEM automotive market, GM was one of our clients. They were trying to get their rep up on being reliable, they pretty much told us they did NOT want the latest and greatest,,,,,,,,,, only proven parts.