1979 Checkmate Predictor Project

[Check_Jo3]

Been getting some of the balsa core out. It is proving tougher than I thought it would be. The rotten stuff is easy but the stuff that is not is a bear. I want to get it all out because my plan was to replace the 3/8" with 1/2" core. I have a lot of hours with the oscillating tool ahead of me . Quite a few spots the factory pulled the roving to much and left holes/ voids in it.

[Check_Jo3]

Welp made a crack in thru the bottom where the bottom turns up to the side. This was in the last chine before it goes up the side and there was no core there. The roven was delaminating so I pulled/pried it up until it stopped doing so. I can't believe how thin the bottom is but I guess that's how they keep these pretty light in combo with the 3/8" balsa. It looks like the factory layup was gelcoat, 1 layer of light CSM, 1 maybe 2 layers of roven in spots where there is no balsa core.

Question to the board.. How thick should the bottom be before putting the balsa core back in? I am now thinking 2 layers of 1708 on the whole bottom as it will be so thin after I scuff it up. This will add weight but I can't mentally wrap my head around going 70+ with it so thin. The outside will need to be sanded pretty heavily; that will take material off as well. I am going to put 1/2" balsa back (the original was 3/8").

[LakeFever]

Shocking isn’t it? When I did mine and realized the outer skin was 1/8” thick ( at most ) I was pretty freaked out. My instincts were to add two layers of 1708 before laying core. Most here seemed to think it was unnecessary and to not add too much weight into the layup. There was a lot of damage to the front of my hull so I did lay double there and the rest got one. Fast forward a year or so and after coring I ran two lays of 1708 over the entire top of core all the way up to the hull lip. My cap was separated for this. Then I laid another layer of 1708 across the entire underside of the hull before gel coat. The transom has tons of layers of 1708 and 1808 and I laid two up both sides of each stringer along with two cap lays. I was worried about all that glass and the weight so after the hull was complete I weighed it. 694lbs. Factory they weigh 750lbs. I used coosa for everything aside from the core.

moral of the story is trust your gut. More is better than less for longevity and strength and imo at least for whatever that’s worth you will end up with a higher quality build. I think the way to look at it is the factory needs to make money and the least amount of materials and labor they can build with is what they do. Hope this is of some help

[Check_Jo3]

Barely got to do anything until recently. Kids, school, work, house projects.. it's always something. 3rd baby is due in June. Got 3/4 of the old glass off the core (Thanks 7" grinder and 24grit pads). Had to make a huge dolly to roll it outside for grinding.. a huge mess in the garage even with drop cloths up all around. Ordered my coosa to try and kick me in gear. 2X 3/4" 26lb density, 2X 1/2" 26lb density and 2X 1/2" 20lb density. I ordered the new balsa too. I ordered it from Harbor Sales here in MD.. great service and prices. Delivery was literally about 12 hours after I put the order in. My house was on the guy's route they didn't even charge shipping. Dropped it off at 1am and helped load it in the garage and wouldn't take a tip. They will definitely be getting my business again on the next project (if I can ever finish this one ). A few days more of grinding, and I'll finally get to the fun part of putting it back together. Also picked up a used but like-new Sea Star Pro helm, just need the lines and a wheel, and I'll have just about all the big hardware-related stuff.

[Check_Jo3]

3rd baby born a week ago. Havnt been able to do much as usual. I did finally get all the roven ground out. Now just the rest of the old core. Checked the compression on the motor and all were above 130 which was nice. Couldn't get it to spit water tho. Impeller looked decent enough so maybe the t-stats were stuck. Then noticed that one of the lines was spitting gas out onto the bottom of the flywheel. Its always something! Been looking into getting the core bond but have seen lake used both B70 and B72.. any recommendations on which is better? I plan to use vinylester on all the glasswork.

[LakeFever]

the only difference between the b70 and b72 is the catalyst is green for b72 and mekp for b70. I liked the green and would have stuck with it but for whatever reason at the time only the b70 was sold in gallons and the b72 was pails. I only needed a bit more to complete the build so I went with the 70. I did notice that the mekp catalyzed version was a little thinner to work with though. Iirc the main reason for the difference was for ambient temperature. Meaning one was a summer deal and the other was a winter. Can’t recall which was which. Both good though. Easy to use. Painful to sand though

[Check_Jo3]

Took a look at the t-stats.. someone help me out here. These look drilled out to me no? Last guy has this on a bass boat and it's got 34cc heads guess he had it hopped up a bit? I have read to generally not run open t-stats on non-race type engines. apologies on the newb level questions

[sonicss33]

Those stats are just cut out meaning someone cut the actual sensing part off and just used the body. Too much flow on those for sure, I don’t think you need to use those. Get new thermostats or you can play around with flat washers and finding the right size hole. Lots of information about that process somewhere on S&F.

[Check_Jo3]

Replaced the leaky line for the top bearing, t-stats and impeller. I started it up on the hose again only to find more fuel leaks and ran out of gas. The fuel lines were held on with zip ties on the barbs. They were loose so I replaced them with hose clamps and they still seem to be weeping.. maybe the zip ties would be better. Also there was fuel collecting around #5 where the water comes into/out of the block? maybe it's a bad gasket. These other fuel leaks besides the top-bearing bleed line would explain the general filthy-ness in the pan. I feared a crack but I think I might be ok.

Now I have these other 2 lines one seems like a bleed line that is just hanging around and the other seems like a vent for the carbs but I don't know where it goes. There's a zip tie on it so I guess it just popped off. Any help would be awesome on where these things go.

[LakeFever]

The line routing is laid out in the manual do you have a copy? I’d strongly advise replacing all the fuel lines at minimum with brand new A1 rated line. I replace all the rubber hoses on motors like this. Cheap insurance and can solve a lot of mystery problems you may run into

[Check_Jo3]

Thanks Lake. I Definitely need to get a manual don't have one yet. Was also going to order some fuel line off of the buckshot site. Just got the bleed lines from there

[skialot2]

Thanks Lake. I Definitely need to get a manual don't have one yet. Was also going to order some fuel line off of the buckshot site. Just got the bleed lines from there

Link to the service manual cover

[LakeFever]

There’s a couple online versions of this depending on the year of your motor. This is the only one I have a link too. Check year and serial number see if it matches. If not let us know and we will dig up the right one

https://www.hedges-uk.com/boat/Merc/...nd%20Above.pdf