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Tired 502 Options

Those are awfully high numbers I assume you made sure that both valves where closed with the lifters on the base circle of the cam. If not then you are getting false readings and with that high of a reading where was the air going into the crank case or out the valves.
 
Check out Ben @ Precision Power/Chief Engines in Spring Lake. They do all the work on our 43' and I trust them completely.
 
check253 said:
Check out Ben @ Precision Power/Chief Engines in Spring Lake. They do all the work on our 43' and I trust them completely.
Click to expand...

Will have to get ahold of them - called a couple of weeks ago and left a message, but I assume they are buried like all the other boat mechanics.

Will be looking to re-power this winter - not a big fan of rebuilding with old / new / repaired parts - don't like trying to save a few dollars now and losing more in repairs and down time later.

Any recommendations for a solid reliable engine for the 253 - I'm not looking to go real fast, but don't want to get passed by an open V sport boat :D.
Will be mostly on Lake Michigan, so WOT with lots of HP is not too realistic on most days with only a 25' boat.
 
Kunkel Auto & Marine

Contact Jason Kunkel the guy is fantastic to deal with and knows his ****.
(419) 529-4446
 
Injectors Cleaned and Installed

Got the injectors cleaned and installed. One was flowing 12% low at higher rpm and was replaced, full set is flowing good now. I'm getting a little more WOT rpm ( 4500 instead of 4400 ) - but would really expect the current 21 prop to run higher rpm than the 23 I tested earlier. ( 23 prop was running around 4400 rpm as well. )

Going to check fuel pressure next - maybe a bad fuel pump / pressure regulator?

I'm not ready to give up on this motor just yet :D

Can still enjoy the boat this summer and will have to evaluate my options this fall / winter when things slow down.
 
Man, something is really wrong if you are only turning 4500 with a 21p prop on that 502. The original motor in my 253 was a 310hp carb'd 454 and it turned a 22p Bravo to 4800. With 100 more hp than I had in the same hull you should be all over the rev limiter (5150rpm I think) in no time with that 21p. Most people with that motor in our hull are running at least a 24p Bravo prop up to 5000 rpm. IMO, if you want it to last the rest of the season (or as long as it can) I would give up on getting any speed out of it. Find a 22p Bravo (will put less strain on the motor getting on plane) and just cruise it everywhere you go. Then this winter rebuild it back to stock and throw a ProCharger on it, or find a fresh hp500 to put in it. Either way you'll have a helluva Lake Michigan boat. When you do get some calm water, would be a solid mid to upper 70mph boat!!
 
needs a valve job at min, 500 hours is about where the heads start showing issues...plus a std 502 EFI is a bit underpowered in a 253 to me
 
I'm not concerned with getting more speed - just want to feel safe being on the big lake and not breaking down. The 21P is fine for now. We mostly just cruise anyway, but it is nice to run fast now and then :D.

Hopefully will find something with the fuel system and get that fixed then I will be more comfortable for the rest of the season.
 
ezstriper said:
needs a valve job at min, 500 hours is about where the heads start showing issues...plus a std 502 EFI is a bit underpowered in a 253 to me
Click to expand...

I was told the heads were fresh - and didn't see any valve leakage when I did the blow down test.

I've pretty much accepted that it needs to be re-powered this winter - just haven't had the time to do a more thorough investigation of my options there.
 
corey331 said:
Man, something is really wrong if you are only turning 4500 with a 21p prop on that 502. The original motor in my 253 was a 310hp carb'd 454 and it turned a 22p Bravo to 4800. With 100 more hp than I had in the same hull you should be all over the rev limiter (5150rpm I think) in no time with that 21p. Most people with that motor in our hull are running at least a 24p Bravo prop up to 5000 rpm. IMO, if you want it to last the rest of the season (or as long as it can) I would give up on getting any speed out of it. Find a 22p Bravo (will put less strain on the motor getting on plane) and just cruise it everywhere you go. Then this winter rebuild it back to stock and throw a ProCharger on it, or find a fresh hp500 to put in it. Either way you'll have a helluva Lake Michigan boat. When you do get some calm water, would be a solid mid to upper 70mph boat!!
Click to expand...

Agree 100% on the ProCharger. I would highly recommend Kunkel Auto & Marine. I have 454 MAG MPI that runs 86 on GPS & starts and runs like stock.
 
Pro-charger

Does a pro-charger run on regular gas or does it need higher octane?

I'm good with more power for the occasional blow someone away, but don't really want to pay 2x as much for premium for the 95% of the time I don't need the extra power.
 
Just about anything you do is going to require something more than 87 octane. But even in stock form, I always ran premium. I figure its not the extra 40 cents a gallon that gets ya, its the fist $2.50/gallon.
 
Yes you will need to run premium on boost. Only way to run regular 87 would be to swap a 500-525 blue motor or have a big inch mild naturally aspirated motor built to have a power gain worth justifying the expense. Prochargers are a good system, but only as good as the person setting them up.
 
Ordered a fuel pressure gauge set from Gaffrig - boat already had gauge installed but not hooked up - no pressure sender. Gauge and sender was only $15 more than just the sender so got the whole set. Hopefully that will shed some light on the problem.
I also checked the oil in the sea water pump fuel pump - seemed pretty thin and smelled like gas - so have a new mechanical fuel pump ordered - fingers crossed :-).
 
Nick616 said:
Does a pro-charger run on regular gas or does it need higher octane?

I'm good with more power for the occasional blow someone away, but don't really want to pay 2x as much for premium for the 95% of the time I don't need the extra power.
Click to expand...

I run 91 Octain e-free. I also add octain booster to the fuel system just to be safe. Jason Kunkel told me the octain boost is a good insurance policy but she will also run fine without it. We live on the lake and my boat is on a hoist all season so I have to purchase fuel at the local marinas and they have all switched to the 91 Octain E-Free. I go hours longer on the fuel this year then last year W/O the ProCharger. I am sure going from a 24P Bravo 1 to the 32P Bravo 1 I run now has a lot to do with it. Cruising at 45MPH IS 2800 RPM AND 1/3 trim.:banana:
 
So I got the new mechanical fuel pump and fuel gauge installed. ( Old fuel pump was nasty )
The gauge sender was a 0-10bar ( 0 -150psi ) and the gauge was 0-100psi ( I have no idea why they don't match . . . ) Fuel pressure read 60psi on the gauge which I assume is 42 psi actual with the sender not matching, which is where it should have been. Took the boat out for a test run. Fuel pressure held at 60 on the gauge up until about 1/2 throttle position then dropped to 50 or less as I went to WOT. 1/2 Throttle was about 3500rpm. When I cut the throttle, fuel pressure would increase to 70, then drop back to 60.
I'm assuming the electric fuel pump / pressure regulator is bad. Anything else I should look for?
 
Did you run a ground wire and attach it to sender body? Those senders are just usually one wire output and ground through threads/housing.
 
Yes - it has separate ground connection, connected to (-) strip in "electrical" compartment.

It seems to be working, other than the gauge reading is off due to the "sender" not matching the gauge range.
 
"Final" update

Got the boat into the shop a week ago - had new cool fuel pump, cooler, and pressure regulator installed. Had a couple of "funky" fuel lines, those were replaced. Alternator was not charging ( only 10.6 V ) - it got replaced now at 13+V.

Finally got out for a test run last night. Fuel pressure was holding at 30psi from idle to WOT - seems a little low, but everything is new so I'm not sure why it is not higher or not increasing with higher throttle . . .
Throttle is more responsive and idles better. But no more WOT rpm - still only runs 4000 with drive all the way down, maybe 4200+ with drive trimmed up.
Water temp ( on gauge ) is around 180 when cruising ( 3500 ) went up to 210 on a short WOT run.

I've pretty much accepted that this is all I'm going to get out of her this year, will enjoy what's left of the boating season, and get the engine rebuilt this winter.

Hopefully next year will be better . .
 
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