Performance on '73, 21’ Chiefton.

[Always Broke]

I’m restoring an aluminum Starcraft Chiefton and the motor is next on my to do list, I’m starting to get a little worried about performance, I hope you folks tell me my worries are for nothing. I bought the boat to restore and never had it on the water. I’ll probably post this same question in the Starcraft forum to cover all the bases. I always had smaller boats with either inboards or outboards with fiberglass hulls, except back in the 60’s and 70’s my family had a 26’, wood, Chris Craft Caviler with a 283 Chevy and a strait inboard. The boat ran like a bat outta hell and would run close to 50 MPH at WOT, we even pulled 10 skiers with it once, ahhhhh the good old days of high compression and good gas. The thing that got me going is I always check the Mercruiser forum for tips and advice while I was freshening up my out drive and see a lot of posts from folks who have around the same size boat 2500# dry, a lot more ponies then my 165 HP rated 250CI six banger, and they are always complaining about lack of power and not being able to get out of the hole let alone pulling a skier. I plan on using my boat for fishing and over night cruising, I’m out of the go fast stage but still got enough kid in me that when I kick the boat in the butt I want er to get up and go, not wallow around like a Manatee. A lot of boats were sold under powered to keep the price down, do I have one of them? I also have not been able to find what kind of compression ratio this motor is running, good gas was still around in 73’ any idea? I probably wouldn’t go as far as to put a V8 in it if it is under powered, it sounds like a good running motor and I hate to get rid of it if it ain’t broke. I would try to make the old 6 breath a little better, it has a manifold that is able to accept a 4BBL with a block off plate and a 2BBL on it and I can always make a little noise with a through hull exhaust.

 

[gspig]

Re: Performance on '73, 21’ Chiefton.

I have a 21' fiberglass boat with the same engine and it's a year older than yours. It's my first boat, so my idea of performance my be different than yours. Mine is built like a tank, so it should be at least as heavy as yours. I think it gets out of the hole well and most certaily reaches plane. I have gps clocked the speed at 35 mph. I haven't had the opportunity to tube behind it yet, so I can't verify its towing ability. Certainly don't count the motor out until you see how it performs in your boat.

 

[Doug Durako]

Re: Performance on '73, 21’ Chiefton.

I had the 1975 version of that motor with a merc drive in a Cobalt that weighed around 3K dry. We put 860 hours on it with no problems burning 10 percent ethanol unleaded fuel the whole time. The valves were hardened and ready for unleaded fuel in 1975, not sure what they did in 1973.<br /><br />I loved that motor! You won't win any races, but it should push you along okay.

 

[Bondo]

Re: Performance on '73, 21’ Chiefton.

Hey, AB,.....<br /><br />I've got a 74 Starcraft 221 Islander,..... It's the Same boat with a slightly lower cabin........<br /><br />The Standard motor was the 140hp, 4 banger...Which is what Was in mine......<br /><br />The Optional power for our boats was the I6......<br /><br />I yanked mine,+ dropped in a 4.3l......<br /><br />I Think you'll be pleasently Surprized how well that old I6 will do for you,.......<br />It's a Torquey old girl........ <br /><br />BTW,...... Our hulls are relatively Flat,.... It'll JUMP out of the water, onto Plane.....<br />These old Tinboats Don't act like a Glass hull.......

 

[Always Broke]

Re: Performance on '73, 21’ Chiefton.

Thanks for all the help, I feel a lot better about that motor now and think it will do what I want it to. I'll let you all know when I get it in the water. I’m still not to sure about what to do with the timing yet not knowing what kind of compression they run. I guess I'll tune it by ear when I get it in the water. What I do with older cars is run mid grade gas, advance it until it pings under load then back it off until it stops, that was the only way to do the old Mopar slant six’s, I never saw one with the timing marks in the right place.

 

[ziggy]

Re: Performance on '73, 21’ Chiefton.

heres a few numbers for ya always broke. these numbers come out of service manual C-90-68648 vol. 2. i think it apply's to yer boat.<br /><br />compressoin-140psi<br />dwell-31 degrees-34 degrees, gap .016"<br />plug gap- .035"<br />timeing at idle rpm- 6 degree BTDC<br />idle rpm- 500-600<br />wot- 3900-4300 rpm<br />fuel pump pressure 3.5-4.5 psi. <br />perhaps that'll get ya started. <br />this engine does seem to be a workhorse and quite durable. <br />also i don't know about yer 73, but my 72 wants leaded premium per the mercruiser sticker on the valve cover......i use a lead substitute with premium fuel. this adding of lead has been covered here on iboats before too and seems debateable. my choice is to use the additive....and i don't like additives either.

 

[qaztwo]

Re: Performance on '73, 21’ Chiefton.

I also had 72 inline 6, great engine. About 5 years ago had to rebuild do to a crack in the cylinder wall. Up untill that point never a problem. I personally put on about 3000hrs on it and most of that was skiing. I also feel the same way about adding the lead sub, although I run the cheap gas(87). The numbers are correct as I also have the old oraange manuals.

 

[SteveNix]

Re: Performance on '73, 21’ Chiefton.

i've got the same engine in a '79. a little newer then you, but the engines run forever, and if something goes wrong...easy to fix too!<br />mine's in a 20' galaxy that is about 3000lbs, and it pulls pretty good out of the hole with my 17P prop.