Crusader 454 with misfire issue

RonR said:

You know I was fighting what I thought was the same issues. I thought for sure it was some kind of ignition problem. New Cap/rotor/wires/plugs... same issue. I checked every wire against the firing order standard and reverse engines. Our engines have low hours so I did not think it was a carb issue. Boat would run fine just enough for me not to pull the carb. But I never could find any stand out problems with the ignition. The miss was always on the same side of the engine, pulled each plug and never really could pin point one cylinder that had the problem, seamed all of the off side were not running right. Pulled the carb off and it was very clean inside. Tore it all apart installed a new kit after a night in the dunk tank and a heavy blow down and clean.. Runs great now! I decided to also pull the other carb and do the same just to make sure there was no junk in it.

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"Low hours" could mean the engines were sitting long enough that the fuel left in the carb "varnished", cluttering up the carb.

menzies said:

"Low hours" could mean the engines were sitting long enough that the fuel left in the carb "varnished", cluttering up the carb.

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They were replaced in 2006 have about 400 hours. But your right it sat for 4 years before we got it. Even when I took the carbs apart they were clean inside. But someplace deep inside it had something in it !

And make sure the right plug wire goes to the right cylinder...

menzies said:

What else would it have been?

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A 350 CU IN (5.7L) Crusader 270hp.

Some people still refer to a 5.7L GM/Chevy Small Block as a 350. They might also call a 7.4L GM Big Block a 454. They grew up seeing these badges on the fenders of their Chevy's.

Crusader has named these engine models 270 (5.7L Small Block) and 350 (7.4L Big Block) referring to HP, not CU IN.

Could be a little confusing for some.

Ignition coils have changed a lot since your boat was new in 1980. Coils with newer designs produce far more voltage. Make sure the plug wires you buy are designed for the voltage your ignition produces.


Make sure your coils are a design compatible with your ignition. Swapped coils with internal/external resistance incompatibility can drive you crazy.

LarryM said:

A 350 CU IN (5.7L) Crusader 270hp.

Some people still refer to a 5.7L GM/Chevy Small Block as a 350. They might also call a 7.4L GM Big Block a 454. They grew up seeing these badges on the fenders of their Chevy's.

Crusader has named these engine models 270 (5.7L Small Block) and 350 (7.4L Big Block) referring to HP, not CU IN.

Could be a little confusing for some.

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Not for those that owned them or the mechanics who worked on them - they were called 454 350s. I owned them for 14 years.

Now I have Lugger 6068T 174s.

:d

I had a misfire in one of mine that haunted us for a year. It was a bit erratic, and would sometimes shut us down. Great old time mechanic (I finally gave up) diagnosed a bad wiring harness. He was right. Good luck with yours!

FWIW. I put Jacobs 8mm silicon wire sets on my twin BB Crusaders. VG quality.

Dave G:


Before you start spending a lot of money replacing parts, first determine whether the misfire is electrical as suggested by Sunchaser. Pick up an in-line spark tester (less than $10) and check each plug and wire. If there is no spark, the test will show it.


If you insist on new plug wire, there is nothing special about 454s. They are basically truck motors and any quality 7-9 mm wire from s speed shop will work. There is no standard for "marine ignition wires", just manufacturer's hype. You probably have wither Mark IV or Gen V blocks, depending upon the year, and a kit will have the right lengths.


If all of the plugs appear to be firing properly after using the tester, look at the fuel system.


I'm running rebuilt Mercruiser 454 Mark IVs in my 1972 Uniflite 36 aft cabin and have spilled a good deal of blood on these engines.


Gene

After market jacobs wires good for bbc at 10 grand no break down hulu

replace plug wires

I routinely replace my plug wires about every 5 years or about two changes of plugs. The wires don't seem to do very well in a marine environment. My twin IH 240 cubic inch sixes have been in my boat almost 60 years and they have always run great by keeping up with routine maintenance!

RonR said:

They were replaced in 2006 have about 400 hours. But your right it sat for 4 years before we got it. Even when I took the carbs apart they were clean inside. But someplace deep inside it had something in it !

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I have seen misfiring where a boat with the same model engines had been idle for a long time. The carb was basically flooding and resulted in the misfiring.

When you say misfire.. Its missing, sputtering and backfiring? Id look at youre fuel filters and water separators... A little water in the fuel will make it backfire pop and spit like crazy. You may have a perfectly good ignition system only to have some bad fuel... do both engines run from the same fuel source? Can you cross fee them?

Sometimes its the little stuff

I once had one of my engines backfiring... consulted a mechanic and he removed my heads and had them redone only to find out it was a bad
$2 condenser/capacitor ... in my distributor cap %*#*#!!!

Bizsoft said:

Hey Guys,

I have 1980 Uniflite 42 DC with twin 454 Crusaders. The port motor has a pretty bad misfire issue. I replaced the cap and rotor, no change. I want to replace the spark plug wires (plugs are also new) but some folks have said that some of the available wires don't work well or are mis-sized. Looking for advice on the manufacturer and where to get the new wires. Thanks in advance for your help. Stay healthy!

- Dave G.

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A good resource for your engines is Iboats forum. Those 454s may still have points and condenser ignition, if not they have the older style hall effect sensor/module. I use to upgrade those with HEI and Accell spark plug wires and E3 plugs. It made a difference in performance and fuel efficiency.



https://forums.iboats.com/forum/engine-repair-and-maintenance

Bizsoft said:

Hey Guys,

I have 1980 Uniflite 42 DC with twin 454 Crusaders. The port motor has a pretty bad misfire issue. I replaced the cap and rotor, no change. I want to replace the spark plug wires (plugs are also new) but some folks have said that some of the available wires don't work well or are mis-sized. Looking for advice on the manufacturer and where to get the new wires. Thanks in advance for your help. Stay healthy!

- Dave G.

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Additional suggestions
1. Test for misfire using an infrared temperature gun. Runs the engine and aim the pointer at each spark plug. Pulling wires also works. Pull at the cap, easier to get to. You can buy a special set of insulated pliers to avoid getting bit. If you plug wires, have someone watch the tach. No change in RPM means that's the cylinder.

2. Look for hairline cracks in the distributor cap, if equipped.
3. Vacuum leaks also cause misfires. Look for missing or loose vacuum hoses. If the mixture is too lean, it will misfire.
4. Finally as mentioned by others this is like an automobile engine. Napa sells good quality ignition wires. Ask for the premium set. AC Delco is the OEM builder of the engine, so AC Delco wires should work fine. Unless you buy from the boat builder or a set specifically for that engine in that boat, be prepared to cut and reattach the wire ends if some are too long. Easy to do. Plenty of YouTube videos on making custom length spark plug wire sets.

Newtrawlerowner said:

Finally as mentioned by others this is like an automobile engine. Napa sells good quality ignition wires. Ask for the premium set. AC Delco is the OEM builder of the engine, so AC Delco wires should work fine. Unless you buy from the boat builder or a set specifically for that engine in that boat, be prepared to cut and reattach the wire ends if some are too long. Easy to do. Plenty of YouTube videos on making custom length spark plug wire sets.

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Ignition wires, distributor connections and spark plug wire end caps are different for a marine application. They were marine rated 50 years ago when I bought my first Mercruiser. Remains so to this day I would guess.

All sorts of stuff that goes into the ER area of a gas boat is different than its auto or shore based cousin. But, not all follow the guidelines and rules when repairs are needed.

Distributor caps and such are definitely different, but I can't identify anything different about the wires or their ends between the marine and non-marine versions. The plug wires all have sealing boots, etc. for both applications.

rslifkin said:

Distributor caps and such are definitely different, but I can't identify anything different about the wires or their ends between the marine and non-marine versions. The plug wires all have sealing boots, etc. for both applications.

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I stand corrected. A look at Marine Parts Source, Thunderbolt Big Block Spark plug wires shows wire ends are stainless. Cars use copper, brass or cheap aluminum ends. The wire itself is a stainless steel wound conductor as well. And the price seems comparable to a premium automotive brand. Thanks for pointing that out.
Here is a link with Mercury part numbers.

https://www.marinepartssource.com/m...park-plug-wires/spark-plug-wire-set-18-8804-1