1963 28hp super seahorse high rev troublshooting help

[59playbouy]

hey gang I just went to test float my boat I have almost finished restoring a 1959 Larson Pla-Boy and I am having some issues with the engine .
It is 63 28hp super seahorse it doesnt want to rev very high , seemed to run great at home in a tank but when I put it in the lake and in gear it wont rev very high it idles great but wont rev up . it doesnt stall out or sputter when trying to give it gas , now it doesnt want to rev in neutral either . I messed with the high and low setting on the carb but it made no difference either way,
I am going to start checking things but I am young and new to the world of outboards.
I am hoping someone can give me a troubleshoot list to through ,thanx guys
P.S I know it is the long weekend so most of you are out ON YOUR BOATS but thanx in advance for any advice I get.

 

[lindy46]

Re: 1963 28hp super seahorse high rev troublshooting help

Probably running on one cylinder - did you check to make sure you have good spark?

 

[jasper60103]

Re: 1963 28hp super seahorse high rev troublshooting help

I have the service manual for your motor. PM me with your email address if you want a copy.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

I have electric choke on my engine and the solinoid is seized so it would not let the butterfly open alll the way or at all really so would this cause these issues? I have moved the solinoid so the butterfly opens now I will let you knw how it goes.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

And YES there is spark

 

[lindy46]

Re: 1963 28hp super seahorse high rev troublshooting help

Sure, if the choke were mostly closed, you wouldn't be getting enough air - too rich. I'm surprised it would run at all.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

I just went a tested it out and the choke wasnt the problem I am going to take the carb apart tonight is there anything else i should be checking..

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

would one clogged jet be the cause ? idles perfectly and rund great at low rpm but wont go to high rpm, but no sputter?
thanx again for the help guys

 

[F_R]

Re: 1963 28hp super seahorse high rev troublshooting help

Pay attention to what was already said. It probably is running on one cylinder. Running on one is an ignition problem, or a no compression on one cylinder problem. It is NOT a carburetor problem, because the carb feeds both cylinders equally. The exception would be if you have the high speed needle open so far you are flooding it to death. 3/4 turn or less is the norm.

Don't overlook the simple stuff (spark plug).

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

I had already said it has spark ..........thank you anyways.
Can someone give me a list to troubleshoot starting with the most likely causes .

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

Pay attention to what was already said. It probably is running on one cylinder. Running on one is an ignition problem, or a no compression on one cylinder problem. It is NOT a carburetor problem, because the carb feeds both cylinders equally. The exception would be if you have the high speed needle open so far you are flooding it to death. 3/4 turn or less is the norm.

Don't overlook the simple stuff (spark plug).

There is good spark on both plugs.
Also When I try to adjust the high speed needle it does absoloutly nothing which is why I thought Carb.......

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

I am holding the spark plug against the block and seeing nice spark on both plugs is there a better procedure for checking spark?

 

[lindy46]

Re: 1963 28hp super seahorse high rev troublshooting help

Yup - get an $8 spark tester at an auto parts store, and see if she'll jump at least 1/4" gap.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

O.K lindy I will pick one up tomorrow thanks. As no one has given me anything else to check I will assume this is the most likely or only cause of these symptoms.
If there is a spark issue what should I start checking and how do i go about it?

 

[F_R]

Re: 1963 28hp super seahorse high rev troublshooting help

All that stuff is under the flywheel. Obviously, you have to remove the flywheel to check it. You need a puller to get it off and a torque wrench to put it back on. Most people use an automotive harmonic ballancer puller. There is no substitute for the torque wrench. Torque is 100-105 ft/lbs. Don't think you can guess at it, that has destroyed many a motor.

You didn't say you tried new plugs.

There is another thing that will make it run on one, a ruptured fuel pump diaphragm. But you say it idles ok, so that probably isn't it.

You say the high speed needle does nothing. It HAS to do something. It simply cannot run if turned completely off. Somewhere before turned compltely off is the sweet spot.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

All that stuff is under the flywheel. Obviously, you have to remove the flywheel to check it. You need a puller to get it off and a torque wrench to put it back on. Most people use an automotive harmonic ballancer puller. There is no substitute for the torque wrench. Torque is 100-105 ft/lbs. Don't think you can guess at it, that has destroyed many a motor.

You didn't say you tried new plugs.

There is another thing that will make it run on one, a ruptured fuel pump diaphragm. But you say it idles ok, so that probably isn't it.

You say the high speed needle does nothing. It HAS to do something. It simply cannot run if turned completely off. Somewhere before turned compltely off is the sweet spot.

Thanks F R, I will do a proper spark test tomorrow with a spark tester , this engine has been sitting for a while should I replace the diaphram even it it hasnt ruptured yet? I will check it in the morning. you are right about the high speed needle it does bog the engine down when turned all the way back but has no effect on the performance other than that. thanks again

 

[oldybutagoody]

Re: 1963 28hp super seahorse high rev troublshooting help

If you have proper spark and it idles but won't run at high rpms it could be your high speed needle setting. I'm not sure if the '63 had adjustable high speed needles or if the have fixed high speed jet but you mentioned two needles so I'll assume it has an adjustable high speed needle. Turn it in all the way (not too firmly so you don't damage the needle or seat) and back it out only 3/4 of a turn. That's your starting point. Now, ON THE WATER, in forward gear, under load, at full throttle. Turn it in slowly about an 1/8 of a turn at a time. It should increase RPMS until you get to a point where it starts to starve for fuel and it will cough or "sneeze". When it does that, back it back out an 1/8th to a quarter turn. and forget it. The low speed needle is similar but it can be set in a bucket in neutral and the intial setting is 1 1/2 turns out.
You issue could be other things like ignition or head gasket but you should rule out the easy stuff first.

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

alright I have done my spark test both plug wires are sparking good. I also started her up in the tank and pulled the plug wires off seperatly and it was definitly running on both cylinders, so now that I have ruled out ignition issues what do I look for now?
could it be high speed ignition problem?
is there such a thing?
checked the pump diaphragm it looked good I am going to order one just in case. what does the diaphragm on the port side do and should it be replaced also?
thanx again guys I am trying to get this boat in the boat show this weekend but it might be a land exhibit if i cant get it running properly in time

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

I replaced the diaphragm it looked pretty strectched out . Still have the same issues tho..... any other ideas guys? the carb is coming off tonight for a cleaning just for fun
thanks again guys

 

[59playbouy]

Re: 1963 28hp super seahorse high rev troublshooting help

is this thread dead... if not.
I took the carb off and I think the previous owner had messed with it. the high speed needle (oldybutagoody) was turned out too far for it to close when the knob was as far as it would go. the adjustment knob should be able to close the needle completly correct?
I will try it out in the morning and let anyone who is still here know whats up.
thanks again guys