62 Speedtwin 28hp no thrust

[timmeraw]

I am working on a 1962 Evinrude Speedtwin 28 hp and it is starting, running, pumping, and idling very well. The problem is that when I water test and try to throttle it up it does not have enough thrust to even get the little 15' MFG(1959- glass hull and wood decks windshield and seats...very light) to a plane.
The engine rpms advance properly but there is not enough thrust.....kinda feels like a car spinning its wheels. I first thought of a spun prop but I marked the hub and the prop and upon return to the dock they were still lined up.

Could it maybe be:
1) something to do with the high speed needle setting
2) gas is mixed pretty rich(about 30-1)......what should it be? Getting mixed messages as I poke around.
3) It has one of those whale-fin things on it which when I look down under half throttle seems to be just gliding on the top of the water?

Ideas graciously accepted and appreciated .

Thanks,
Tim

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

Try adjusting the high speed needle with someone driving the boat at full throttle. Adjust to optimum speed. If that doesn't work, have you checked spark? May be running on one cylinder. Do you have a tach? How many rpms at full throttle? Engine is designed to run 24:1 gasil mix.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

It is definately not a problem with running on one cyl. I can try adjusting the high speed needle again but it will just adjust the rpm's I am assuming. Just by ear I can tell RPM's are increasing well with throttle but it is not correlating to
the increased speed of the boat. I doesn't have a tack.

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

Well, if you have good spark on both cylinders, a clean and properly adjusted carb, and the prop hub isn't spun, then I'd be checking compression.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Compression is 90 on both cyls. I have not removed and cleaned the carb as it is working pretty well. It has a slight miss for a few seconds at cold start(especially if I don't throttle enough to start position) but after a very short warm up it purrs like a kitten.

I have removed the whale tale thing and changed the lower gear lube again(it was fine).

I wonder where the proper initial setting for the low and high speed needles is before tweaking on the water? The high speed only moves from 10 oclock to 2 and the low is about 8 oclock to 5 or so.

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

You have to remove the low speed knob and reverse it so it doesn't hit the stop. Close the needle gently, then open it 1.5 turns for initial setting. Disconnect the high speed knob rod from the needle, so you can do the same thing - close the needle and then open it about 3/4 of a turn. Once you get high speed adjusted by running at WOT on a lake to optimum, then re-connect the knob/rod with the "arrow" end of the knob pointing straight up. Tighten it up. Do the same with the low speed once it idles good.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Thanks Lindy...did that. Still an issue. After another test in the water today I fear that it may only be consistantly running on one cylinder. It idles ok but at 1/4 cruise along it seems to jump ahead for a second and then let off. I have spark on both but maybe it is a coil or points issue. Just tried to remove the flywheel but the nut is stuck bad. I don't have a tool to hold the flywheel.
Any ingenious methods out there. I had it in gear, blocked the prop with a 2/4 and also used a big screw driver across the flywheel splines and the block but still won't budge. Even applied some heat from a propane torch to the nut but no budge.

It appears that the plug wires and fuel lines have been replaced so I kinda assumed that maybe the coils were too but without pulling the flywheel can't tell.

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

Probably a coil cutting out. To remove the flywheel, put a long bolt in the back hole where the recoil starter bolts down. Then wedge a piece of hardwood between the bolt and the flywheel teeth. Have a friend hold it in there tightly, then try to remove the nut. Those nuts are torqued down to 100ft.lbs so they can be a bear to remove. It may take an impact wrench to get it off.

 

[Tim Frank]

Re: 62 Speedtwin 28hp no thrust

More info needed....
1) Is this combination new to you? i.e. did it ever give the performance that you are hoping for?
2) Have you checked tilt? It may be tilted too high and planing out will be tough....drop it a notch at a time and see if there is a difference.
3) You may need to get a tach to see what is really happening...the prop may not suit if it is new to the boat.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Probably a coil cutting out. To remove the flywheel, put a long bolt in the back hole where the recoil starter bolts down. Then wedge a piece of hardwood between the bolt and the flywheel teeth. Have a friend hold it in there tightly, then try to remove the nut. Those nuts are torqued down to 100ft.lbs so they can be a bear to remove. It may take an impact wrench to get it off.

Ok ...good idea with the bolt. I actually used a spare pull cord ..wrapped and tied to bolt. Came of with some major pressure.
Now of course the flywheel is pretty stuck. Got the puller going ...... sitting with penetrating oil now. Nothing is easy.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

More info needed....
1) Is this combination new to you? i.e. did it ever give the performance that you are hoping for?
2) Have you checked tilt? It may be tilted too high and planing out will be tough....drop it a notch at a time and see if there is a difference.
3) You may need to get a tach to see what is really happening...the prop may not suit if it is new to the boat.

Tim,

Yes this is a motor that came off of similar MFG that was recently purchased and promised to have been running well. I have tried all tilt positions with no diff. Working on pulling the flywheel to check the coils and points etc.

 

[Tim Frank]

Re: 62 Speedtwin 28hp no thrust

Provided you have the 3-holes in the flywheel, make yourself a special-purpose flywheel locking tool. You are in upstate New York, so should be able to get your hands on an old/broken old hockey stick.
Cut ~ 2-1/2' off the handle.
Drill interference/on-size holes, preferably with a drill press, on the same c/c distance between two bolt holes at one end.
Bolt the handle firmly onto the flywheel and you have an extension to oppose the wrench you use to crack the nut.

Have someone else on the hockey stick at 180 degree angle, or do it yourself at lower angle, but watch your knuckles.

1/4" x 1-1/2 " alum or steel bar is probably better, but not as cheap.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Ok I quit....this is not my motor. I struggled to the get the nut off and now I have been working on getting the flywheel to pop. No go.... I just partial stripped out one of the 3 flywheel holes when one of the grade 8 bolts snapped. I am not even positive that it is a coil or points or condensor problem.

I am going to send it back to my buddy with my tail between my legs trying to feel good that I got it pumping well with a new impeller and idling nicely.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Ok so this motor is haunting me and I can't stand being beaten by it. Would a cause for no high end thrust have anything to do with the gear control not engaging it far enough into forward position? Logic tells me it is either in gear or not or the clutch dog would be barking....but maybe I will take her for a spin and disengage the shift cable and run it manually.

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

I doubt the problem is in the gearcase or linkage. Those would cause jumping out of gear or intermittent bang like you're hitting a log at high speed. Lack of power at WOT would probably be either a spun prop hub or running on one cylinder due to a failing coil. If it's revving up to where it should, or sounds like it's over-revving, it's a spun hub. If it feels like it's not reaching proper rpm's, then it's running on one cylinder.

 

[timmeraw]

Re: 62 Speedtwin 28hp no thrust

Wow dejavu... I was just water testing a 58 Evinrude 454 and in low to middle throttle it was banging just like hitting a log...very litterally. Full throttle no problem and slow idle ok also. We also found it would not engage reverse because of cable setting so maybe it was not fully engaging FWD either.
Nothing to do with the other 62 28hp issue but good thoughts.

 

[chadchappell]

Re: 62 Speedtwin 28hp no thrust

did you check for spun hub on the prop, had a similar issue with my '62 28hp, put a new prop on and it was fixed

 

[samo_ott]

Re: 62 Speedtwin 28hp no thrust

I agree, I'd revisit the spun prop and 100% verify that it is ok.

 

[kbait]

Re: 62 Speedtwin 28hp no thrust

Do you have a short-shaft motor mounted on a long-shaft transom? It'll never plane out, and sound just like a spun prop.

 

[lindy46]

Re: 62 Speedtwin 28hp no thrust

Year+ old thread.