Is my motor sick or am I underpowered?

[sgobat@msn.com]

I have a 97 Evinrude 28 Special on a 16 foot Smokercraft Pro Alaskan. The boat with motor, gear and passengers weighs in at about 1,000 pounds.

The motor starts easily and seems to power up well but I cannot get the boat on plane. My speedo says I am going about 10 mph at WOT. I do not have a tach.

Is the boat weight to much for this engine or should I be looking for something wrong on the engine itself.

Any advice is appreciated!

 

[HighTrim]

Re: Is my motor sick or am I underpowered?

I would start by testing spark on all cylinders. The spark should jump the 1/2" gap with a strong blue ZAP!! You will need an inline tester for this.



Is this boat new to you, or did it just start acting up?

 

[tashasdaddy]

Re: Is my motor sick or am I underpowered?

i don't really know your boat. picture would help.

you can up load to a free service like photobucket.com then you choose the pictures you want( clik the little box at the bottom left of the picture) scrool to the bottom of the page, clik generate html, it will take you to the next page, scroll down to thumb nails clik on that and copy, then insert it into your post.

also if you are planing on posting pictures, you can use the Blue post reply or the go advanced, manage attachments, there you can upload , directly from your computer. besure you pictures have been resized to fit the format. 640x480 max.

 

[kenmyfam]

Re: Is my motor sick or am I underpowered?

Set up / trim/ motor height is important. Some photos would help and a more detailed description.

 

[HighTrim]

Re: Is my motor sick or am I underpowered?

This is the 15', but same idea.

I would say you are underpowered for that boat. Wish we knew your WOT RPM. What prop are you running?

"http://www.boatquest.com/All/Manufacturer/Category/Length/47051/Feet/USD/1/boats.aspx"

 

[tashasdaddy]

Re: Is my motor sick or am I underpowered?

as kenmyfam said, set up, do you have correct shaft length motor for the boat? is all the weight in the stern of the boat? how many people are aboard.

 

[ezeke]

Re: Is my motor sick or am I underpowered?

The boat is rated for max 60HP which puts you low with your existing setup. I believe that you can still get on plane with a lower pitch prop than you are using. Take the pitch as low as possible. You will not have a fantastic top end, but you will do a lot better than you are now. I would not be surprised if you are running with the propeller that originally came with the motor.

If you are running with a jet drive, you have little chance of improvement.

http://www.iboats.com/Smoker-Craft_Boats__16PA2_Pro_Alaskan__1997/bp/64b82024r1

 

[tashasdaddy]

Re: Is my motor sick or am I underpowered?

i that is the case you are way underpowered. minimum 45hp.

 

[sgobat@msn.com]

Re: Is my motor sick or am I underpowered?

Wow! Thanks for all of the advice.

The boat is new to me but I was told that 10 mph was top end when I bought it so I was not suprised. It didn't occur to me to adjust the trim (I have been away from boating for several years), I left it where the previous owner had it. So I will try that first.

I had the motor checked out and serviced (new water pump, check plugs etc) by a marine mechanic who said it was in good shape, I will ask him about the spark question.

The observation regarding the prop is probably correct. I would also bet that it is the original prop. The shaft length is correct, the cavitation plate is about an inch below the bottom of the transom.

The foto that was posted is pretty close to my boat, only difference is that mine has a full windshield and dual consuls so it is a bit heavier. Most of the weight is from the consuls back. The built in gas tank sits in the stern under the floorboards.

The load on the maiden voyage was myself (190) and wife (160) along with our Golden retriever (60 and growing) so estimate about 410 lbs plus the two motors (main 130 lbs, kicker 100 lbs). Add in about 12 gallons of gas at 8 lbs each (rounded to 100 lbs) and miscellaneous gear (20) . That comes to 720 lbs plus the weight of the base boat at 540 so total load is probably pretty close to 1,300 lbs.

I do not have any fotos yet, the camera went on the fritz the day we took the boat out. Thanks for the advice on how to post them though.

I will ask the mechanic about the spark plus try adjusting the trim first then look to the prop. Again thanks for all of the excellent comments, i Boats is a great resource.

 

[kenmyfam]

Re: Is my motor sick or am I underpowered?

If your motor is set up correctly (many posts and threads out here about this) and propped more to suit your set up you should see improved performance, however you are asking a lot with the load you state you have aboard and that you are a little under 50% of the max HP for your outfit. As stated earlier if set up and loading of your boat are optimised hopefully you can get it up on plane. That is the "biggie" at this point.
Good Luck and please keep us all informed of your progress.

 

[tmcalavy]

Re: Is my motor sick or am I underpowered?

Step to at least 35 hp minimum, or just hang another 28 hp off the transom. With twin outboards you always have a backup motor to get you home...not hard to rig or maintain if you do your own work.

 

[ezeke]

Re: Is my motor sick or am I underpowered?

The weight of twin motors will probably overwhelm the boat, (and double your troubles). Finding a counter rotating 28 special is probably impossible anyway.

You have a good 30HP motor that is readily marketable because it is the right motor for a 14' V hull light weight aluminum boat like Lund, Starcraft, Smokercraft, etc.

I would think about trading up to a larger engine.

In the meantime, you could raise your engine at least to the point where the anti-ventilation plate is in line with the keel.

OMC had a 11 X 9 prop #386317 that has superseded to #763487. Michigan Wheel has a 11 X 9 # 012054. At around $100.00, it would probably be worth a shot at raising the engine and trying the lower pitch propeller.

An even better possibility would be OEM Prop # 387320. At 11-1/4 X 7, You would have an even better chance of getting on plane and being able to raise the engine by at least one hole.

Both of the OEM props are available from your OMC/BRP dealership.

They sell the MW props here at iboats. In my experience with iboats, they have shipped from the manufacturer and been delivered to my home within 4 days.

 

[sgobat@msn.com]

Re: Is my motor sick or am I underpowered?

Thanks once again.

I pulled the existing prop off. It is a 9 X 12.

The question now is will the OEM Prop # 387320, 11-1/4 X 7 fit. On the existing prop there is about 5/8's of an inch clearance between the top of the prop blade and the bottom of the ventilation plate. The 11-1/4 diameter prop will add 1-1/8 inch to the travel arc. Not enough room if diameter is the only factor.

If the 7 pitch lays flatter than the 12 pitch the recommended prop might clear the ventiation plate. Although the diameter is still 11-1/4. Confused, you bet!

I have found several OMC 11-1/4 X 7 props that are available and they all say they fit most newer Evinrudes from 20 to 35 hp. Just want to be sure before I order one.

 

[sgobat@msn.com]

Re: Is my motor sick or am I underpowered?

Correction: I cleaned the prop up a bit more and the number on the prop is 9.2 X 12, OMC#389944. Michigan Wheel list this as a 9 - 1/4 in by 12.

Regarding your other suggestions: I can raise the motor one hole, without having to drill new holes in the transom. Doing this would put the ventilation plate more or less even with the bottom of the keel. Although this would mean the motor bracket would be sitting above the top of the transom, so I assume I would need to put a spacer in to help carry the weight of the motor to the transom.

As far as loading goes. The boat is rated for 1,300 lbs, people, motor and gear. So at 700 to 750 lbs load l am just above mid-range for loading although distribution of the load is an issue since most of the weight is from the consols back. I will redistribite the load as best I can.

 

[ezeke]

Re: Is my motor sick or am I underpowered?

No, don't buy it. Go to the 9-1/4 X 7 OEM prop Part # 389067, instead.

The 1997 parts catalog doesn't list the drive, so I made a couple of erroneous assumptions about which drive you have. Sorry, I won't do that again.

Go to the 1996 parts catalog and you can get a list of props that were marketed with your drive. http://epc.brp.com/default.aspx?brands=ej&lang=e

Look at the parts list under the gearcase diagram.

 

[sgobat@msn.com]

Re: Is my motor sick or am I underpowered?

Well I took the boat out today. With the original 9.25 X 12 prop and the motor trimmed all the way into the transom, the load distributed as far forward as possible and carrying 160 lbs less weight I was able to get up on plane immediately and topped out at 21 mph. The boat ran smoothly, slightly bow up.

So I am thinking that if I add the 160 lbs back in (my wife) I may need to drop to a 9 X 11 or 9 X10 prop and /or add some Smart Tabs. Hopefully this will eliminate the need to put out several thousand dollars on a new motor.

Thanks for the help.

 

[tashasdaddy]

Re: Is my motor sick or am I underpowered?

move the motor up one hole, the 4 bolts hold it on. you don't have to put the spacer under it. that will reduce drag, and improve performance even more.

 

[iwombat]

Re: Is my motor sick or am I underpowered?

You'd be a lot better off raising the motor at leat one hole too - and no you don't need a spacer.

Your anti-ventilation plate should be even with, or 2" ABOVE the keel of the boat. If it's currently below the keel of the boat, that's most of your problem right there.

 

[steelespike]

Re: Is my motor sick or am I underpowered?

Its so great to see someone be successful with a few tips.It would be good to get an rpm reading.Its important for your motors health that it operate
within its reccomended rpm range.4,500 to 5,500 rpm.

 

[sgobat@msn.com]

Re: Is my motor sick or am I underpowered?

I went online the other day looking for a tach, specifically for boats, but did not have a lot of success. I was looking for one I could install permanently with a guage on the dash.

Any recommendations?