1978 Viking rebuild

[Baker343]

Glad to see you finally get it wet. I don't know your hull but they were built to perform. I do know 2L and I would stay in the 26p area. I run a 24 Mazco on a mildly ported 2L with 26cc heads 79mph at 6900rpm's in sprint racing.
I ran a 26 chopper/dunamus cut by Steve Smith in the Enduros 83mph at around 66 to 6700rpms for many hours.
Depending on your 2L health it can live at 6700.
So I would run 24's and 26's to get your rpm's up.
Test test and test. Interior and extra body weight is always a challenge.

[rjdubiel]

That stinks. Was just going to let you know we will be on the river Friday morning.

[tnelsmn]

New Atlas plate arrived in time to have it on for father's day weekend! The new plate gives some room to adjust a bit more than the L&S plate did. I have the plate in its top hole to set it as low as I can on the transom, and the engine is in the middle hole. This puts the prop shaft about 1/2" above the pad with the plate full up. I'm still trying to make this boat pull double duty as a ski boat and speed rig.

Still working to get it to break 70 at this point. I did a compression check which I'll list below. The best I've seen so far is 69 at about 6,200. Thats with a 26 big ear chopper, running about even to 1/2" above. It just seems like it runs out of power there. Going to get a spark gap tester and see if there's any weak coils. Also thinking I may add a few more degrees of timing. It's currently set at 20BTDC cranking speed at WOT, thinking of bumping that to 22, maybe 24? It still seems to be a bit weak out of the hole pulling a skier too. Adding the dole-fin made a huge help and 100lbs of weight in the bow helped more as well.

I have a 28 Mazco on the way that I just picked up as well. Prop collection is growing haha.

Compression test numbers, engine cold, throttles closed.
#1, 120
#2, 113
#3, 125
#4, 115
#5, 125
#6, 118

[XstreamVking]

Left bank has better compression. 120-125 is considered good stock. Rt side is not critical low, but is pushing the 10% margin. Max timing at 23 deg is safe if good gas is used. (91-93 octane) More timing and you need to check the actual timing of each cyl. They can vary 2-3 deg sometimes. Good to check timing variance anyway.

[LakeFever]

Maybe time for a little head shave

[tnelsmn]

Ok, I think I'll bump the timing a little bit then. I was considering taking some off the heads but don't want to go that far with this motor considering I have the ProMax about ready to go on. Just waiting on the boat side harness to arrive, which is on back order.

[LakeFever]

Funny that’s exactly why I was thinking shave the heads. If it works? Great! If not? Promax time LOL

I’ve taken sled heads off, had em shaved, and reinstalled in two hours for all. It’s a couple of gaskets and 30 mins for the machine shop if you have one you know or are friendly with this helps

[mrichartz]

Ok, I think I'll bump the timing a little bit then. I was considering taking some off the heads but don't want to go that far with this motor considering I have the ProMax about ready to go on. Just waiting on the boat side harness to arrive, which is on back order.

I would't cut the heads now keep them stock..well not like you can't find them but..
If it's weak save it to rebuild you did an awesome job on everything else..well I guess it depends on what you want to do with it in the end too?
But it's like putting a bandaid on and again look at what you did to the rest of the boat...
Just bump the timing

[Blacknsilvr]

I wouldnt say it’s weak. Hell,a decarb could bring those numbers back up. These boats take time to learn how to drive, and I’m still learning mine. Put a few degrees of timing to it, safely. It’s the cheapest and quickest option.

[mrichartz]

Yea how long has that motor been sitting till recently?
Did you put any seafoam etc in?

But if your going to do it..DO IT..cut them to where you need 104 octane and turn up the timing etc...and run it!!
Will be over 80-5 then...
JUST KIDDING..don't ruin that motor....just stop waiting throw the promax on and get going....you don't have to pushbthe throttle all the way you know..lol

[Blacknsilvr]

Yea how long has that motor been sitting till recently?
Did you put any seafoam etc in?

But if your going to do it..DO IT..cut them to where you need 104 octane and turn up the timing etc...and run it!!
Will be over 80-5 then...
JUST KIDDING..don't ruin that motor....just stop waiting throw the promax on and get going....you don't have to pushbthe throttle all the way you know..lol

lol this guy gets it!! Save the 175 for the next boat. 17-19 ft center console to cruise around on. We call them beer drinking barges down here.

[mrichartz]

It's a nice �� old clean freshwater motor right?
You never know what the next boat is and what you need motor wise...and they don't make them anymore and what they do ARENT cheap...

[rjdubiel]

That 1978 motor with the 3 ram clamp is work 1500+ easy, I am saying 2K with the lower! Leave it alone, crank up timing and go. Switch to the PM once you can.

[tnelsmn]

Boat side harness for the PM is on back order till August otherwise I'd be working on switching it over now. I'm going to call around locally and see if anyone has one on the shelf.

Yep, old freshwater motor from the north, so been stored every winter. It had been sitting about 15 years, I did pull and rebuild all the carbs before it went on the boat. I'll get the timing done this week and try agin. I ran the 28 Mazco this morning, seems like it wasn't lifting the bow. I think it needs more cup.

[rjdubiel]

I can drop off that cracked 30p small ear, zip it up and run it and see how it does. I don't think I will run it anymore on my boat anymore. Plenty of bow lift on my vking.