HELP ...----- Hesitation at 2300

[Mark Albers]

Donzi Aficionados wink

HELP !!!

I noticed hesitation at 2,300 RPM
I recently change my manifoilds (Hardin)
The 22 (OMC 454 King Cobra) was running strong for a while then it would not climb higher than 2,300

I thought the new bracket I added to the Spitfire gismo was not grounded properly
I added a second ground wire and noticed no problem for a while
It would scream to 4,300 RPM
The next day out it ran fine for 30 minutes
and
Then acted up again (not wanting to let me go pass 2,300 RPM)

After coming to a stop and resting for @ 5 minutes
I switched over to batterty #2 (just for the hell of it)
and she ran strong again

I dont know if it was the resting/cooling down, switching the battery or just something loose (electrical)

What do you think is going on here ???

Thanks

Mark 311 :cool:
Sarasota - - - W F O (close to the factory and far from a dream)

[tailwind]

Check both your intake manifolds, and carb gaskets - too lean a mixture possibly.

[MOP]

Mark does it start to run rough or does it run smooth. Any spitting or back firing. Have you pulled the spark plugs to see if they indicate a lean condition, if so were all the plugs the same color hopefully dark brown to black with no carbon deposits. You may have to re-jet the carb, a good set of headers make the engine go lean how lean is the ?. Lean is bad, check for that. Try to get some ideas from guys up here about the possible need to re-jet. I have always been a firm believer in reading the plugs after any engine modification it like saying stick out your toungue to an engine.

[GeneD]

Switching to battery 2 may have provided you with the answer.
Check the alternator.

[Woodsy]

Gene hit it on the head.... If switching to Bat #2 solved the problem, and it doesn't act up again, then I would give the charging system a good look, starting with Battery #1... sounds like it might be down on voltage, maybe an internal short. Then look at the alternator, however, if Bat #2 is charged ok.... back to Bat #1....

Woodsy Von Donzi

[Mark Albers]

Gene :confused:

I did have a problem with battery #2
(it would not take a full deep cycle charge)
This is do to the previous owner running them at the same time)

Why would changing to a differnet battery affect it ???

Dosent the motor use a low voltage at speed ???

How do I check the alternator ???

Thanks for all your help !!!

Mark 311 :cool:
Sarasota - - - W F O (close to the factory and far from a dream)

[HyperDonzi]

changing out mani's, maybe a air leak, running a lean mixture will make an engine HOT, when an engine gets hot, it looses power, whats your temp gauge say when it screams and when it only goes to 2300??

[Donzi Blackhawk]

Mark,

Give me a call, I have equipment to test all of your engine woes.

Bryant

[HyperDonzi]

does anyone else think that there may be an air leak or did my head leak apart? changing manis, runs good then after 15 min of cooling, runs good??? maybe a little bit of an overheat?

[Tidbart]

Possibly Whippin Boy, but first things first. The batteries are a known problem. Look at them first, correct them if necessary, then look at the charging system, correct it if necessary. Now you may have corrected the problem or eliminated the charging system as a source of the problem. Batteries and charging systems are a relatively easy fix. Now you can move on to other areas.
I guess what I am saying is start with simple and basic possibilities first.

Bob

[HyperDonzi]

ok, i agree, start first things first and if they dont work, put new gaskets in.

[Formula Jr]

It may very well be the battery, but I have to ask the question as to why would he have been able to start the motor up with bat #1 if his voltage was so low that it would not run the ignition?

[Mark Albers]

Formula Jr wink

I did have some weakness in starting the boat a couple of times (forgot to mention)

I am going to check the electrical system this weekend

Thanks for everyone's input/output

Hyper Child .... takes some ridlin :p

Mark 311 :cool:
Sarasota - - - W F O (close to the factory and far from a dream)

[Formula Jr]

Mad P. is dead on with load testing also. If you just do a Volt test it may not tell you the whole story. Tested alot of batts. that will say 13 or so volts but there's almost no amperage: they act like a capacitor sometimes when they have cycled so much, or been cooked a few times, that the plates are not uniform anymore. So you end up with a static 13V, but the effective cranking power of the bat. is almost nil.

[MOP]

Looks like electric is your run problem, but its is a good idea to check your plugs for color. This is best done on a flat calm dalm day, run the boat at high cruise say 35-3600 for a full 15 minutes. Throttle back and shut it down, do not idle back to a dock the idea is to get good clean readings whether good or bad you want to be exacting. Take the plugs out and compare them to a plug chart, a good color is dark tan. Too dark or Too light jetting of the carb or a metering rod change will be nessesary. You will also be faster set up properly, if you were a fuely the computor should take care of this. As a carbed boat you are now running atleast a little lean.