Loss of MPH
 

97 27 Fever 321 hours 502 Mag

When I bought the boat it would run 68 all day long. Ocassionally faster if all the stars aligned. This season the fastest I have seen is 63 (barely) and that is with 4 people full tank of gas and almost perfect chop to run in. I know its only 5 mph but now I am a little sluggish getting out of the hole. Oil pressure is still very strong and have changed oil and lower unit gear lube at the beginning of the year. I used to be able to hit the rev limiter easily but now, not so much. I think it is worth mentioning i have not changed props.

I have ordered a new fuel filter, distributer cap, wire ignition kit, rotor and spark plugs from BAM. To my knowledge they have not been replaced. I would be SHOCKED if the previous owner replaced them.

I have also noticed more smoke than normal when starting and burning 1/2 qt of oil every other fill up.

Also, I was thinking maybe sending my prop off at the end of the year to have it worked on. Any suggestions on that and do you think it is worth it?

I have ABSOLUTELY NO idea how well the boat was taken care of before I owned it so I don't know how hard (or not) it has been run.

Do any of you know if this could fix my problem or is that just part of the life of the motor? The factory paperwork says 68 WOT.

I am by no means a boat mechanic but have a friend that is very knowlegable and have been able to learn a lot from him just knocking around the garage. So anything too technical is WAY over my head.

Thanks for any and all input!

Your boat sit in the water a lot?

Only on the weekends. Saturday morning (occassoinaly Friday night) put it in and pull it out Sunday afternoon.

If I'm at the coast it comes out every day.

I have made one trip up the river to Chattanooga and it sat in the water for 3 days.

Also it doesn't stay near water like on a lift. It always sits on a trailer in the carport or warehouse.

Couple of things are you comparing apples to apples, at 68 was it loaded with a full tank of fuel and 4 people or not. I find it hard to beleive a 27 with a 502 would hit almost 68 fully loaded.

Either way 5mph could mean a alot of things, water temp might have a play, obviously conditions would, but fuel could be a factor, oil, prop had dings and dents in it. You could replace the things you are talking about but generally I dont think your going to pick up 5mph with all of that.

The boat is 15 years old, how many hours on it, and has it ever been rebuilt. If it has more than 4-500hours on it, its probably getting tired, which doesnt mean it needs to be replaced now, but just to watch it and if it gets worse stop running it.

Personally 1/2qt of oil every other time depending on hours might be a that things are going bad, maybe your oil pump is on the fritz which is kicking in more oil making the engine work harder. Also it MPI or carb, either way either of those could be dirty or need adjustment.

Really there lots of things to check, personally I would run it for rest of the summer, and this fall next spring have it inspected.

321 hours, never rebuilt, orginal engine, MPI, yes it would do 68 all things equal on GPS, actually the only time I saw faster than 68 was in salt water PERFECT conditions with only 2 people. I have only ran salt water maybe 3 weekends at the most. I'm 5 hours from salt so I don't get down there too much. ( I know the next question I will get is do I flush it, the answer is yes. I even run salt-away through before I put it in the water and then again when I pull it out. Maybe a little too paranoid)

I have a brand new water pump (housing, impeller everything) but I have not put it on the boat. I just have it "in case" if you know what I mean. I have never replaced it and never have seen that much difference in the gauge reading. While I'm in the engine compartment this weekend should I just go ahead and throw that on there as well? I have never done that job but doesn't look like a hard one from what I have read online and watched on youtube. I have TONS of room in the engine compartment! I hope one day thats not the case. :whistle:

Changing the water pump or impellor would have no bearing on MPH unless it is grossly overheating. With unknown history and 300+ hours, I would do a cpmpression test on each cylinder. If you have weak compression on any or all cylinders, you are losing horsepower and need to be considering rebuild/repower in future. Even if all in the 150 PSI range, good to have benchmark numbers for future comparision.

that would be my guess as well is your losing compression. You could have that tested now for free or fairly cheap to rule it out. Even if its getting bad, youll be fine rest of the summer. All the Maint things you are talking are good to do but like boats said unless any one of those things are grossly malfunctioning they are not a culprit of mass HP loss.

You switch octanes, maybe try some new gas with stabil. Also I know on my 454 87 gas runs better than premium on my boat.

Thanks for all your input. I will get a compression test done sometime. That is a good idea.

As far as gas goes, I run 87 "with no ethanol" but I still use stabil. The place at the lake advertises no ethanol but I don't think its the best fuel in the world plus you never know what kind of fuel the truck hauled before it dumped the "no ethanol" in the ground for this particular place.

Well if I'm able to get all these things done this weekend I will keep you updated but I'm not holding my breath and will continue to enjoy my boat.

I guess I need to start a "re-build fund" nontheless... not sure I am ready for the 35.....yet

It may be worthwhile to get your fuel tank to half or less which is about 35 gallons in your boat I think and run some fuel injection cleaner through it.

Also check underneath the hull to make sure you dont have a lot of buildup and its smooth, i know some guys claim that by waxing you can pick up a few mph. Also check all compartements and bilge for water. Every fountain Ive ever heard of cant seem to keep water out and the way they sit you cant always see the water. So maybe try tilting it up to make sure you arent carying a few extra pounds.

But with more oil consumption Im guessing compression like we said or your mpi unit is faulty/dirty and really being that old and hours its not uncommon for a tune up or rebuild.

But you should be fine to run just monitor everyhting and ensure you dont have a melt down as your rebuild could be significant larger.

Did you change oil filter or oil types this year.

If you lost 5 mph during winter storage, I would check for a hook. If the boat was winterized properly, I see no reason why it should be an engine problem. Just my o2