Mid-90's 270 Sundancer Thread

[B Morton]

Starting batteries provide a lot of cranking amps for the heavy draw from a motor, but once the motor is running, that demand drops out. Using a refrigerator while under way isnt a problem at all. I wouldnt recommend relying on a starter battery for usage while anchored and expecting it to keep you running for 24 hours long, but its more than enough for a few hours. Your best bet is to keep your battery switch to your starter battery while starting and underway, and feel free to use any of your DC devices while you're running, but once you stop, switch over to your house batteries and use them for all your DC

Thanks Sicktght311, that’s how I will run it from now on!!

 

[Sicktght311]

Thanks Sicktght311, that’s how I will run it from now on!!

NP. This is all of course under the assumption you're connected to shore power when you're done with your day, allowing both batteries to stay fully charged. If your dock space doesnt have shore power, and you're relying on the motor to charge your batteries, then you will want it in the "Both" position while the motor is running. 1 to start it, Both for running, 2 for house battery when anchored

 

[Nginear]

Just recently replaced the thermostat in my 97 7.4L carbureted merc with standard cooling. According to my serial number and the online parts catalogs plus the boat repair shop I went to when I broke the plastic retaining spacer it takes a 160* thermostat. The one that came in the engine when I bought the boat 2 years ago must have been a 140* as that is what the gauge always read( 140ish or 12 o'clock on the gauge face).

I've searched the forum and have seen people say because it's standard cooling it should have a 140 but none of the info I find through searches agrees.

So my question is what thermostats are you guys running if you have the same engine configuration? I'm sure a season at 160 isn't going to affect anything just want to know for my own knowledge.

 

[Sicktght311]

Just recently replaced the thermostat in my 97 7.4L carbureted merc with standard cooling. According to my serial number and the online parts catalogs plus the boat repair shop I went to when I broke the plastic retaining spacer it takes a 160* thermostat. The one that came in the engine when I bought the boat 2 years ago must have been a 140* as that is what the gauge always read( 140ish or 12 o'clock on the gauge face).

I've searched the forum and have seen people say because its standard cooling it should have a 140 but none of the info I find through .

So my question is what thermostats are you guys running if you have the same engine configuration? I'm sure a season at 160 isn't going to affect anything just want to know for my own knowledge.

If you have raw water cooling, 160 degrees is the OEM thermostat. The 140 is for closed cooling

 

[Sicktght311]

If you have raw water cooling, 160 degrees is the OEM thermostat. The 140 is for closed cooling

Actually scratch that. I didnt see you have carburated not MPI. If i remember correctly based on previous posts, the 160 thermostat is for EFI/MPI, and the 140 is used on the carbureted 454s.

 

[Nginear]

This is from an online parts catalog I found. For my serial number (which seems to only apply to one model year of engine 96-97) it shows the thermostat as 160*.

Maybe I should email Merc and see if they have an opinion.

 

[Sicktght311]

Stick to what the serial number recommends. The next years moved up to MPI. We have a 99 MPI and its 160 as well

 

[Nginear]

Stick to what the serial number recommends. The next years moved up to MPI. We have a 99 MPI and its 160 as well

I went through the three options in the merc parts catalog looking at thermostat temps and found this info

7.4L Bravo '88-91 used a 140* in both new and old thermostat housings

7.4L Bravo Gen V '92-96 came in two options. 140* or 160* depending if there was a heat exchanger or not.

7.4L Bravo Gen VI '96-97 uses a 160*

Looks like everything after uses a 160*

I tired emailing and calling Merc directly but both options don't work. The telephone support is just an endless loop of no one is home and the email "contact us" gave me an error each time.

 

[gatorm]

Boo! Somebody needed to say something in here. It’s winter time in TN with snow on the ground and I have cabin fever. Cheers!

 

[89P270]

So, ive been a way for a while and thought I'd come back to share some recent work ive had done on the 270. I had noted in a few other threads (or maybe above) I was going to use inject-a-deck to do a fiberglass core repair. After purchasing great gobs of the stuff along with the applicators, wringing my hands alot, a coming into a bit of spare cash, I decided to have the core repair done professionally. When I bought the bought back in 2019 I new there was core rot around the front bow hatch and a self repair was always in my future plans. But, unfortunately at the time, I didnt check around the entire foredeck to see the situation around the back foredeck hatch. That was by far worse (area B first photo). I was lazy about where I measured with my moisture meter at the time of my survey and only later at home did I notice the weakness around that back foredeck hatch. See first photo -Note area A is where I had used a 3/8" 2 foot long drill bit (with vacuum) to gow-out the rotten core between the upper and lower gel surfaces. After considering the quality of the self repair with Inject-a-deck and the larger size than what I had originally thought vs professional repair, I bit the 15K bullet and had the professionals repair. Again, the first photo shows after the top coat removal and how extensive the rot was. The next series of photos are throughout the repair process by the professionals. A completion, its much stronger now that OEM with the marine grade 3/8 plywood installed in the core. When I say stronger, the OEM style included 3/8 thivk 3"x3" squares laid in and fiberglassed around vs my current repair which includes scored 3/8 plywood installed to match the foredeck surface. I got a custom skid pad surface as well on the finished surface that I havent got photos of yet but will post a few when I have a chance.

BTW -The rotten core was a result of prior owner not paying attention to hatch seals. Had they paid attention, they could have avoided this 15K bill by simply rebedding the hatches in 3M 4200. I recommend to everyone you rebed your bow hatches regardless of whether you think they need it or not at least every 5-10 year. Inspect every year.

Now that the foredeck repair is complete, I am moving on with a high performance refit of the BBC. Hope to get 430HP out of the refit and should have done in 2 months. Will post update of that when Its complete. WIll likely have to reprop the BIII due to increased HP and will likely go with Hill Marine 4x3's as well.