Motor or prop ?

[AQUA222]

Recently while out in the Long Island sound I've noticed a few quirky things about my 22-2 ff I\O 470 "Morgan Joy". When I accelerate hard fully loaded the rpm's come up but the boat doesn't get going right away. I know a certain amount of the lag is normal, but lately I've noticed if there is a tidal rip or any chop/ turbulent waters this lag is greatly exaggerated. Is this normal? Have I begun to spin the prop hub? Last Saturday I braved 30knot winds and 3 foot seas and lost control docking knicked the prop on a shallow rock but the issue has been noticed long before that. I've also notice when I run hard, say 25mph 3600 rpm for long amount of time 15. Miles or so, when I turn off the motor it "diesels" for a couple second. Only when I run hard other than that it runs great.  And lastly I noticed that there Is a sticker on the gunwhale that say " only use 89, research 93 octane in this motor". What it research 93, I've been using pump gas 87. Should I change octanes? Thanks guys. This boat would not be where it is today without you!

[Capt. Bob]

when I turn off the motor it "diesels" for a couple second.

This can be caused by several things such as carbon build up, "hot dome" on piston or low grade gas. Easiest way to check the last is to fill with a higher octane/grade (super/ethyl/high test or what ever they call it nowadays).

I noticed that there Is a sticker on the gunwhale that say " only use 89, research 93 octane in this motor". What it research 93, I've been using pump gas 87. Should I change octanes? Thanks guys. This boat would not be where it is today without you!

Seems the fuel sticker is indicating a mid-grade octane (89). Appears you are using a lower grade (87). This might be the cause of your "run-on". "Research grade" aka RON is one of many ways fuel grade is measured. Used in the US, wiki "octane" and you can read the numerous ways the world grades gas. 93 RON would equate to mid-grade.

Again, before you dig down deep into this, I'd fill the tank with 91 octane (RON 95???) or whatever the highest (most expensive) grade available at the pump. Run a tank or two through the system and see if anything changes. If so, then switch back to the less expensive mid-grade (89).

Easy stuff first.

Good luck.

[AQUA222]

Thanks Capt. I'll try it, any thoughts on the prop lag? Or whatever is causing my acceleration issues?

[Capt. Bob]

Thanks Capt. I'll try it, any thoughts on the prop lag? Or whatever is causing my acceleration issues?

As you stated above, I would look at the prop hub first. It is a likely candidate and is the easiest thing to check first before moving to other causes.

Easy things first.

Good luck.

[Aswaff400]

470's are finicky when it comes to fuel quality. is yours a 2 barrel or 4 barrel? points or electronic ignition? we always ran rec90 ethanol free in our motors.

[fitz73222]

Recently while out in the Long Island sound I've noticed a few quirky things about my 22-2 ff I\O 470 "Morgan Joy". When I accelerate hard fully loaded the rpm's come up but the boat doesn't get going right away. I know a certain amount of the lag is normal, but lately I've noticed if there is a tidal rip or any chop/ turbulent waters this lag is greatly exaggerated. Is this normal? Have I begun to spin the prop hub? Last Saturday I braved 30knot winds and 3 foot seas and lost control docking knicked the prop on a shallow rock but the issue has been noticed long before that. I've also notice when I run hard, say 25mph 3600 rpm for long amount of time 15. Miles or so, when I turn off the motor it "diesels" for a couple second. Only when I run hard other than that it runs great.  And lastly I noticed that there Is a sticker on the gunwhale that say " only use 89, research 93 octane in this motor". What it research 93, I've been using pump gas 87. Should I change octanes? Thanks guys. This boat would not be where it is today without you!

I've not seen a prop hub "half slip" usually if the prop hub is spun, it won't even get on plane. This is if you are running a conventional pressed in rubber style hub. If you have a flo- torque replaceable plastic hub then maybe it could act as you describe. Pull the prop, make sure the thrust washer doesn't come off with prop and block your view of the pressed in rubber or the plastic flo-torque insert. So you may have to pry the thrust washer off of the prop and put it back on the propshaft in the same orientation as it came off. Some thrust washers are stepped and only go on one way.

As far as dieseling when you shut it off, there are a couple of things.
1) octane and carbon build up as Bob said
2) over advanced timing at idle, this usually makes the engine turn over hard when starting like the battery is weak and you get that "wha, wha, wha" and then it lights off and runs (sounds like a Aamco commercial) lol
3) idle speed too fast caused buy timing, carb adjustment, or intake manifold gasket vacuum leak or vacuum line leak. Do a vacuum test from a vacuum source on the intake manifold. Should be 17-21 on the vacuum gage with no needle fluctuation at idle. Are you hearing any hissing at idle? Also check for loose carburetor mounting bolts.
4) engine temperature starting to creep up from thermostat, plugged heat exchanger, exhaust manifold or riser. What is your engine temp on your gage when running it hard?

Are you getting any vibration when you nail the throttle and the rpm's come up and the boat speed isn't responding?

I'm inclined to think this is carbon build up as Bob has pointed out so try his suggestion first. Also dump a couple of bottles of Mercury "Carbon Free" or "Quick Clean" in the tank when you put some higher octane fuel in it. It will remove any deposits on the piston tops and the valve seats.

[AQUA222]

 Hey Arron/ fitz... Good to hear from you guys, always value your experience and knowledge, my 470 is 2 barrel and is in great shape, low hours, clean and I've gone through it. Fits, I've been running sea foam by the quart the last few tanks, but will switch to the treatment you suggested and run a hight octane. I need to put a timing light on it and see where I'm at with the timing, I have put it off because it has been running great. Always wanted to hook up a dwell meter and eventually switch to the pertronix but previously when I installed the electronic ignition ran way worse than without.  I will check for leaks like you said. I put the boat in forward not running and blocked the fly wheel and tried to spin the prop on the hub and it did not move so I'm rule ing that out. I think I may have been overloaded, I'm 240 my dad is 280 and my bro is pushing 300 so between the three of us, 65 gallons of fuel, fishing gear for all the hot species in Long Island waters, 12 bags ice 3 coolers for food and drink..... Cargo was probably close to a 2k lbs .

[Aswaff400]

with a heavy load the 170/470 is a little underpowered. we have a pair of of 170/470's in my dads boat, '86 Sea Ray 270AJ, and even with a light load she's underpowered. we did electronic ignition and alternator conversions

[AQUA222]

Just an update, did 30 miles Saturday in the Morgan Joy with about half the load I had last time. Ran great planed fast and handled as it should. I also marked the prop shaft and prop and the marks were still aligned when we pulled the boat out. Thanks for your ideas. So here's the developing dilemma, I wash the entire boat after a fishing trip to get the salt and fish guts off the hull and deck, I usually clean the motor and wash the bilge as well. When I opened the cowl there was an oily spray scattered though out the bilge, and was concentrated in certain spots. Any ideas? I never lost oil pressure, there is a small drip of motor oil at the fuel pump but I don't think it could cause the spray. I wiped the bilge clean with a handful of paper towels so it wasn't much, smells like motor oil. No noticeable oil from oil filter or oil pan. What else should I check? Oil level was low but within hatch marks on the dip stick.......

[fitz73222]

Loose oil pressure sending unit

[futch13]

^^^^^^^^^^This Or make sure the oil fill cap is on and breather hoses are connected to valve cover(s)

[AQUA222]

I'll check and get back to you, thanks