454 Crusaders topping out at 3600 RPMs at sea trial

Veg

Veg

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At sea trial, engines seemed to run well, but both topped out at 3600 rpms. Towards the end of sea trial, the surveyor had them run briefly one at a time to WOT, with the same result. They both behaved the same.
Expected to see them over 4k RPMs... Otherwise everything seemed to run well.
1988 carburated Crusader 454 inboards (straight shaft velvet drives) and 17,000 lbs. boat. Only 508 original hours on the engines (ugh).
Will be asking to check accuracy of gauges, but otherwise, thoughts? Overpropped? Something else?
 
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Yeah, should probably be 4400-4600 rpms. Question for the owner, what did it do the last time it was WOT? What was cruise? What GPS MPH did you get? What boat? Could be a few things -- everything from props to gas.
 
Growth on the hull? Otherwise they may be overpropped.
 
What did the surveyor have to say about the WOT?
 
Veg said:
At sea trial, engines seemed to run well, but both topped out at 3600 rpms. Towards the end of sea trial, the surveyor had them run briefly one at a time to WOT, with the same result. They both behaved the same.
Expected to see them over 4k RPMs... Otherwise everything seemed to run well.
1988 carburated Crusader 454 inboards (straight shaft velvet drives) and 17,000 lbs. boat. Only 508 original hours on the engines (ugh).
Will be asking to check accuracy of gauges, but otherwise, thoughts? Overpropped? Something else?
Click to expand...
Did the boat get on plane? Speed at 3600 rpms?
 
I've replaced several twin Crusader distributors on boats in our marina due to rusted advance springs. They all behaved like you described.
You can't run a single engine on a twin and expect WOT even on a boat with engine running good.
 
Boat had just been pressure washed for survey, no fouling.

It has been sitting all year (probably most of the 3 years with current owner) with minimal use.

Surveyor identified the problem, suggested further investigation. I am requesting additional steps now. It's not the only issue that came up with survey, thought it's in the top 3 list of issues I'm digging into.

The boat did plane (not sure if this will work). Video taken on Lake Michigan last Friday:

drive.google.com

IMG_7264.MOV

drive.google.com drive.google.com
 
Does it have the original ignition? Points? I had to replace the original distributor in the port engine because it wouldn't reach 2400 rpms. The weights/springs were so rusted, they couldn't expand. Installed D.U.I in both and never had another ignition problem.
 
Update: In cleaning out the boat, we found the original specifications sheet. In it, the original value for propeller size (at sea level) of 17x18 has been whited out and replaced with a 19x21 value. It reinforces my suspicion that the boat may be overpropped.
 
Ok, a couple of things…not sure what you should have, but 17 x 18 sounds way too small for 454’s.
2nd…you had a survey done and it should have included out of water inspection by the surveyor. He should have confirmed prop size.
3rd…500 hours on 33 year old engines? Sounds awfully low. Maybe the boat is used very little and gas is old and stale.
All that being said, still sounds like you are over-propped and if so, how long has the boat been like that and over-propping strains the engines and shortens their life. Anyway, a red flag.
You need to confirm what props are on the boat and what Should be on the boat.
 
Yes the survey confirmed 19x21, I just found it interesting that the value had been whited out on the docs from the original specs.
Yes the boat has been used very little and the gas is old and stale, no question about that. (The broker told us he saw the owner take the boat out twice this year). The engines will be getting a thorough look over/diagnostics and tuning in the spring. I may replace distributors even as a preventative measure... but I'm interested in taking a closer look at the propping over the winter. I'll also be doing hoses, belts, etc.
And yes, it's a red flag, but it's not even the biggest LOL. We bought the boat knowing it will require significant investments (our project list right now has about 150 items).
(***For context, in case I seem a bit flippant about the possible issues: Most other boats we looked at/considered were much more expensive than this one, with 427 blocks that really did give me pause... We assume these will need rebuilds at some point, but we'll see! We definitely didn't buy this boat to save money in the long run, it's a (fun) project, but we did buy it for about a quarter of what we thought we'd spend on our next boat, and we are ready for serious investments in improving it. Sometimes when you find the boat you want, you just need to go for it, especially if it's not a very common model/layout. And when we're done, basically everything will be new LOL... we're pretty excited about equipping a boat that we really like, in just the way that we want! We basically bought the classic lines, woodless hull and stringers, and some nice teak work in the salon. The rest is up to us. And we do have the Tiara to keep us boating if the project runs a little long...)
 
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my 454 XLs came stock with 18 X 15 props. Reaches WOT rpms easily. CWMS, to know the correct prop, need to know the transmission reduction. For example, my prior boat with small block 350s ran 18 X 18 props but the reduction was way different.
 
I have confirmed with owners of the same hull that their boats are propped 17x18.

I am convinced this boat is over propped, and trying to decide between re-pitching or buying new props. As a surprise, we found a second set of brand spanking new 19x21 set of props last weekend, when deep cleaning the last compartment we found under the inside corner of the salon couch. So we have TWO sets of 19x21 props, one likely never used.

Gear reduction is 1.88:1 ratio (Velvet)

WOT: per the original engine manual included in the boat documents should be 4,200-4,400 RPM for these particular blocks.

I've been on the phone with several prominent prop shops that have been nice enough to provide some insight... General advice has been to try re-pitching the props first. Seems like taking 2" off the pitch would be possible, and I am told to expect another 400rpms as a result. If that pans out, I'd be over 4,000 but not quite in the 4,200-4,400 range. But I am taking weight off the boat (including the generator and ice maker), and cleaning and painting the bottom.... So I wonder if it would end up being real close.

Opt 2 is to sell the 4 props I have which might just buy me a new set of 17x18. Then I'd be back to factory... Though, I wonder if it would seem somewhat under-propped especially with the weight reductions. I am going to work with my local prop shot to determine the best route.
 
If it was my boat, I'd go back to original. Also, If I saw a surveyor at sea trial try to run on one engine at a time up to WOT, I'd have to knock him off the helm. Can't be a good thing to do!
 
You should try to get a set of the smaller props and sea trial again before spending money on new props. See if a prop shop would be willing to lend you a set befor you buy or a friend that may have a set lie what you need.
 
If I was convinced that swapping props is going to happen I'd sell the unused props. Then I'd re-pitch the old ones, get the boat the way I want it, and see how things pan out. One of the trade offs is getting hauled out to swap props a few times. Check out the short haul rates.
I don't have a handle on what over propping a gasser does to low end economy but I am thinking it will be detrimental to normal cruising (on plane) speeds. Depending on the cruising that is planned I might just jump right to the OEM spec props. Are you going to load the boat up and travel or keep it light?
 
Ernesto, Dan brings up a good point, you may need several hauls to get it right. Spring launch time will be problematical as marinas are usually tightly scheduled. See if your prop shop can drop you two inches before launch. If that is not enough then sell your unused set and get originals. The set you drop 2 inches will still be good "get home" props. It is what I have for my boat and I have had to use them.
 
I like that strategy Gary! As several of you know, this is a project boat so I am in no rush. Cruising this year will be minimal, if it happens, so I can just put the re-pitched props on and test them the (likely few) times that we take the boat out of the slip this summer... What I'm looking forward really is to working on the boat at the slip rather than in a warehouse... but it's still going to be a project summer.
My guess is we'll be splashing a bit late, after the rush, and if the re-pitched props don't work out perfectly, I can wait until later in the season or even next winter to put new ones on.
Dan - boat stays pretty light. We spend most nights at our home slip, and by summer 2023 hope to be staying out on the water for 2-3 nights at a time, in the Apostle Islands area (where we slip).
 
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