Coleman 15hp down on power..

[Markopolo]

Well, helped my father recently get his outboard back into shape, now it runs well, however, it feels(and sounds) down on power, were getting only 15mph out of it when it should have been able to do atleast 25 no problem.

I cleaned out the entire fuel system (carb, pump, filter, tank, line and all)

From what I know it's atleast 10 years old (Coleman f15bm is the model) and it's been neglected (family's boat, you know how that goes)

I've been temped to use engine restore as a way to get some compression back (I'm assuming low compression, although it starts and idles fine)

Anyone used the stuff in outboards? I've used it in small engines with good success, I'm just wondering if it would be safe to run in a outboard.

 

[ripcord]

Well, helped my father recently get his outboard back into shape, now it runs well, however, it feels(and sounds) down on power, were getting only 15mph out of it when it should have been able to do atleast 25 no problem.

I cleaned out the entire fuel system (carb, pump, filter, tank, line and all)

From what I know it's atleast 10 years old (Coleman f15bm is the model) and it's been neglected (family's boat, you know how that goes)

I've been temped to use engine restore as a way to get some compression back (I'm assuming low compression, although it starts and idles fine)

Anyone used the stuff in outboards? I've used it in small engines with good success, I'm just wondering if it would be safe to run in a outboard.

No, no, no on the engine restore stuff on 2-cycles. I would have a good look at the exhaust and make sure its not all carbon-ed up and restricted. Outboards can run cold and are more prone to carbon.

 

[Markopolo]

No, no, no on the engine restore stuff on 2-cycles. I would have a good look at the exhaust and make sure its not all carbon-ed up and restricted. Outboards can run cold and are more prone to carbon.

Ah, my bad, should of mention this is a 4 cycle motor.
I was thinking carbon build up as well, possibly adding seafoam might help, any other "good" carbon cleaners out there? (Crc?)

 

[Jetronic]

check the carb is working as it should, acceleration enrichment etc...

 

[RTexasF]

If there is a carb kit still available buy it and use it. When they sit for a long time the carb is very likely the issue.

 

[BigCahuna]

Before you spend more time and effort on the motor, what condition is the hull in? . Is it clean ?. Years back I went away for 2 weeks in the summer. My boat was docked in salt water, so when I got back I tried taking it for a ride. Felt like I was dragging the anchor. Turned out to be the beginnings of barnacles forming, and green slime on the hull. I cleaned it off and picked up 10 mph. Slime will cause drag on the hull also. You would think it might make the hull slide thru the water easier, but that's not how it works. Just a thought.,

 

[xgmad]

Inspect everything, if you see abnormal carbon anywhere, then use a good gasoline like shell and you could use seafoam.

 

[Kawiguy454]

+1 carb kit. I have seen old gasoline change the tolerances on brass jets, needles and emulsion tubes. check compression, If compression is good all that's left is fuel and spark.

 

[Markopolo]

Thanks for the replies, hull is in good condition, I know for a fact carb is flawless, seals are all good, I cleaned every orifice in the carb.


Did a compression test today, the top cylinder is 145ish, the bottom is 95ish

Both plugs had some minor oil residue in it, not sure if it's from the valve seals or the piston rings.

also, the top looked like it burned properly, bottom seems to be bit more oil soaked (due to little to no combustion, i think)

I changed the oil on it, added a bit of restore to it, hopefully, it brings the compression back up.
also changed the plugs for good measure.

 

[ripcord]

Sounds like it could use a valve job or rings.

 

[Markopolo]

Sounds like it could use a valve job or rings.

Yeah, unfortunately being a clone of a rebrand of a clone, parts are IMPOSSIBLE to find for it, even the "genuine" parsun motors aren't very well supported since it's basically a Chinese Yamaha clone.
Was a good price though, believe it was only 1200$ new when we got it.

I think we will just run it hard tomorrow and see if performance improves any.

 

[danez_yoda]

with low compression like that run low octane fuel. 87 max. If you're lucky the bottom ring is just coaked up. Maybe a treatment of berryman B12 in the cylinder head is in order.

Also do the simple and check valve the lifters. one may be too tight allowing leakage. could be very simple.

 

[Markopolo]

with low compression like that run low octane fuel. 87 max. If you're lucky the bottom ring is just coaked up. Maybe a treatment of berryman B12 in the cylinder head is in order.

Also do the simple and check valve the lifters. one may be too tight allowing leakage. could be very simple.

Thanks for the tips, I checked valve clearance and there in spec

We took the boat out today and ran it for 30 minutes, now we are averaging 18mph and it seems to have more bottom end grunt then before, I suspect that the more we run it, the better it will be.

 

[danez_yoda]

a good stiff dose of seafoam has done wonders for me. not the smoke show on youtube but dump about 5 oz per gallon in the last gallon of the tank and run it. this is 5x the maintainance dosage, techron is another good alternative,

the berrymans is very good at loosening coked pistons. also ringfree by quicksilver (mercury).

no magic potions but if the engine is just carboned up. these can work. of there is a mechanical problem. need to fix that.

 

[FastLane]

No way a 15hp is pushing a boat to 25 mph.

 

[Markopolo]

No way a 15hp is pushing a boat to 25 mph.

It should with a 1448 Jon, trust me, we tested it

 

[FastLane]

It should with a 1448 Jon, trust me, we tested it

My Merc 30 pushes my 16 foot Lund tin can to 25. I can do 27 on a cold morning with just me in the boat. My boat is pretty light and has a v hull.

 

[FZ1]

Well, helped my father recently get his outboard back into shape, now it runs well, however, it feels(and sounds) down on power, were getting only 15mph out of it when it should have been able to do atleast 25 no problem.

I cleaned out the entire fuel system (carb, pump, filter, tank, line and all)

From what I know it's atleast 10 years old (Coleman f15bm is the model) and it's been neglected (family's boat, you know how that goes)

I've been temped to use engine restore as a way to get some compression back (I'm assuming low compression, although it starts and idles fine)

Anyone used the stuff in outboards? I've used it in small engines with good success, I'm just wondering if it would be safe to run in a outboard.

Check the condition of the prop and prop shaft. New aluminum props are $75. 3 blades are slightly faster: 4 blades are smoother with a better hole shot. Go down 1 inch in pitch if you go to a 4 blade. Hope this helps.