1967 Seahorse 3hp wont rev up

[JONESN]

Howdy! Just bought a 1967 Johnson Seahorse 3hp SN-82752702 Model#JM22C. When I went to p/u the unit it ran for a couple seconds and stalled out not to crank again. Then got it home and it did the same thing. Proceeded to clean the carb and put fresh gas mix in the tank. Now it does stay running and will crank on first pull but runs rough and will not rev to full power. It seems to run at idle speed and wants to stall out when you try to rev it up. The unit I was told has very little time on it and looks brand new so I do beleive the seller. Would it be the air fuel mix needle or exhaust ports? Thanks in advance! >>> JONESN

 

[jbjennings]

Re: 1967 Seahorse 3hp wont rev up

that '67 has the universal magneto which is notorious for the coils going bad. They probably haven't been changed. You need to get a $6 spark tester at autozone and check spark on both cylinders. I suspect you have weak or no spark on one cylinder due to a bad coil ($25 part) and the motor is only running on one cylinder. You will be shocked how well that motor will run with 2 working cylinders! There's a thread in the "top secret files" of this forum that will show you how to fix points and coils on motors with the universal magneto.
good luck,
JBJ

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Thanks JBJennings! My buddy came by to look at the spaks statis and I do have fire on both cylinders. Also would the coils go bad with very low hours on the unit. So you think the spark may be weak? What should the meter be reading? Thanks JONESN

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

oops

 

[F_R]

Re: 1967 Seahorse 3hp wont rev up

The coils go bad from deteriation of the epoxy covering and they crack with age. Has nothing to do with the run hours.

Having "spark" can be very deceiving. It should be capable of throwing a 1/4" spark. First things first--have you tried new spark plugs and checked compression?

Do this: Remove and ground one spark plug wire and see how it runs. Then do the same thing with the other wire. Chances are, it won't make any difference with one wire grounded, but won't run at all with the other one grounded. That is the good one.

One thing for sure, it isn't the exhaust ports.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

OK I tried the spark plug wire removal thing and it will not run with the lower plug wire off and no effect with the upper removed. Whats next?

 

[crxess]

Re: 1967 Seahorse 3hp wont rev up

Time to pull the flywheel. Inspect coils, points and condensers. Replace as needed.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Sounds like FUN! Ive looked at the TOP SECRET section for the info. Any thing else Ill need.

 

[tx1961whaler]

Re: 1967 Seahorse 3hp wont rev up

A harmonic balancer puller with grade 8, 1/4-20 bolts needed to take off the flywheel. Replace the coils, points and condensers while you're under there and you won't have to look at it again for another 40 years. You need a feeler gauge to set the points at 0.020". Make sure the points are spotless, even though they are new.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Thanks tx1961whaler Ill get back to yous guys next week or so. Also where to get those parts? Points,Condenser and coils that is. Would there be a kit with all the parts needed that I can purchase?

 

[tx1961whaler]

Re: 1967 Seahorse 3hp wont rev up

All are available here at iboats

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Sorry Im kinda new at this boat motor thing. I will need 2 coils one for each plug, 1 condenser and 1 set of points correct?

 

[samo_ott]

Re: 1967 Seahorse 3hp wont rev up

Each ignition circuit is the same. There is 1 coil, 1 condenser and 1 set off points for each plug/cylinder. The condenser's and points come in a kit of 2 each. The coils usually come separately. When you change them, do one side at a time so that you can look at the other side to make sure you're putting it back together correctly.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Thankie mucho samo!

 

[tx1961whaler]

Re: 1967 Seahorse 3hp wont rev up

Points & Condensers (need 1 kit):
http://www.iboats.com/mall/partfind...&gd_poid=111576&gd_row=3&**********=209803156

Coils (Need 2)
http://www.iboats.com/mall/partfind...gd_poid=109172&gd_row=10&**********=209803156

Impeller:
http://www.iboats.com/mall/partfind...&gd_poid=355299&gd_row=2&**********=209803156

Carb Kit:
http://www.iboats.com/mall/partfind...&gd_poid=109333&gd_row=3&**********=209803156

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

When you say the points need to be spotless do you mean clean them with alcohol or what and how and what parts of the points need to be cleaned the contacts?

 

[lindy46]

Re: 1967 Seahorse 3hp wont rev up

New points? Just clean the contacts with solvent and install them.
Used points? Use a point file or fine 400grit emery paper and clean the contacts.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

Another question >> What lb/ft of torque do I put on the crank bolt at the center of that pesky fly wheel??? Then Im done and ready for a test run in the ole test bucket.

 

[lindy46]

Re: 1967 Seahorse 3hp wont rev up

Another question >> What lb/ft of torque do I put on the crank bolt at the center of that pesky fly wheel??? Then Im done and ready for a test run in the ole test bucket.

40-45ft.lbs.

 

[JONESN]

Re: 1967 Seahorse 3hp wont rev up

All righty then > I replaced the coils, points and condensers and it still runs as it did before.I also broke the brass pin in the prop hub trying to get the fly wheel torqued on. My next guess is shear pin for prop,spark plug wires and checking compression correct? Anything else need to be looked at before doing this and in what order? Im having a tuff time navigating and finding parts on this site for the year I have: Thanks JONESN