7.5 Clinton Sea King - Troubles and Questions

[engineerlutz]

Hello, I've read this forum for some time now while working on this old Clinton Sea King that my friend asked me to fix.

I should start by saying the engine I?m working on is a 1977-78 Clinton Sea King Model KTV52307 Clinton Mod K753. I've had a tough time finding the specific manual for this engine but with the combination of other Sea King manuals I have been able to get most of the basic maintenance done.

When I received the engine it had been sitting outside on the boat exposed to the elements and not run for about 3 years. My friend had complained that it was really hard to pull to start but seemed to run fine once it was started.

When I got it into the garage, the shifter was stuck solid along with most of the bolts. After carefully taking off the cover and the pull start I immediately took off the carburetor and found it to be dry and clean. I put it back on and began to look at the lower unit.

The lower unit on this model must be very unique because there seems to be no way to get it off. I couldn?t find a way to disengage the coupling for drive. No access holes, nothing. Only screw holes i could find were the ones at the exhaust port and the recessed bolt on the leading edge just in front of the water intake. I drained the lube from the lower unit because it looked like it needed a change (it was dark brown and was the consistency of peanut butter). Replaced it with new lower unit gear oil. I didn't bother to take apart the gear housing and the prop.

I managed to unstuck the shifter with weeks of wd-40 and a mallet. I?m not sure if it engages the prop, and I fear it doesn?t. When I turn the starter by hand the prop doesn?t turn. My only hope stems from when I tried to start the motor, I noticed it turned the prop to a different position.

About this time I got some new gas and mixed it 1:50 with outboard oil (before i read to use chainsaw oil). With the engine primed and put back together I gave it a few cranks.

This thing about pulled my arm out of it's socket. took about 10 pulls and it wanted to start and even burped out some exhaust but the pull to start the thing is so much I couldn?t do more than 10 tries. I was also worried about the stress on the parts with that much force.

I took off the starter again and noticed that one of the teeth that grab the power head was worn. It has about a 1/4 inch gouge in the tooth. There are 4 teeth, 2 engage to turn the power head.

Now i put it to you guys to help me out.

What can i do to ease the pulling force on the pull starter so I don?t damage the starter and my arm?

Is there any other maintenance i should conduct on the engine?

What is the secret to getting into the lower unit to check the impeller (I?m fairly certain it has one)?

Is there a way to make sure the drive rod actually turns the prop without starting the engine?

This engine wants to run, I can hear it, I just need to make it easier to start so I can fiddle with the carburetor adjustments.

Any advice and comments are appreciated. Thank you for your help in advance. If any of you would like to see some pictures, i can provide them.

SL

 

[steelespike]

Re: 7.5 Clinton Sea King - Troubles and Questions

How does the flywheel turn by hand?How does the recoil operate when off the motor?How does it crank with the plugs out?Most small 2 strokes turn so easyly that you can spin the flywheel by hand and a good running motor will start.
What is the compression?My 89 after market manual says no lower unit service info was available at the time of publication. According to my manual the 753 has a full gearshift.Blowup of the gearcase resembles your typical outboard.In order to shift when not running you need to rotate the prop or flywheel as you shift.I believe if you drop the gearcase you may be able to see the shift rod connector in the crack and remove or loosen the nut.There is no instruction for these models.
I think if you have removed the 2 bolts that hold the gear case it should drop off.You may have a corrosion problem keeping it from coming apart.
Drive shaft my be seized in the crank.
You really need a manual at least there is a blowup of the lower unit and mid section.You may find a manual at the library.I got mine off eBay for about $15
Some times the drive shaft will be stiff where it enters the gearcase making it difficult to turn the driveshaft/flywheel.

 

[engineerlutz]

Re: 7.5 Clinton Sea King - Troubles and Questions

The flywheel will turn by hand but it considerable force to turn. I have to use both hands on the outside of the fly wheel to turn it.

The recoil operates well and works when off the motor.

I haven?t cranked it with the plug out. Why would I want to do this?

The engine has good compression and doesn?t sound like its leaking.

I?ve been afraid to really torque and pull on the lower unit after I get the 2 screws off but I?ll give it another try. I really hope the drive isn?t all corroded. I?ll break into the gear case and lower unit this morning and see if something is obstructed.

 

[steelespike]

Re: 7.5 Clinton Sea King - Troubles and Questions

It definately sounds stiff.I don't think removing the plug will show much.
You may be able to peek in through the plug hole to see if there is any scoring of the cylinder or excessive carbon on the piston. There is a chance you can remove the pinion gear inside the gearcase and pull the drive shaft out as you drop gearcase.You may not be able to remove it all the way but may be able to drop it enough to figure if the shaft is stuck in the crank
By the way it does have an impeller.

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

There are 6 bolts on the underside of the engine. 4 of them are one size and the other 2 are smaller. After you take them out be careful as when you pull the L/U off there is a washer, spring, and fitting that engages the engine to drive the prop that may come out (do not lose any of these). there is also a retainer clip that is on the drive shaft that the washer sits on, then the spring. The other fitting sits in a U shaped bracket that engages the engine by moving the shift lever.

In regards to getting to the impeller, I removed the L/U from the engine and then the prop box from the L/U with the nut an screw you mentioned earlier. the impeller housing sits on top of the gear box (lack of a better term) there are 2 screws you need to remove to get to it. The impeller is held in place with a roll pin. I could not tap mine out I had to drill it out. A quick piece of advise, go get a carbide or Titanium bit as highspeed steel is too soft to drill it out.

If you have any other questions let me know as I am rebuilding mine also.

Brian

 

[yanker]

Re: 7.5 Clinton Sea King - Troubles and Questions

Hi LXIX,

I'm also working to try to replace an impeller on K753 and having problem
getting to the impeller. If you pulled lower column off the power head, did you also have to replace the water plate to column gasket and other gaskets that power head rests on ?? Seems like it is lotta work just to replace impeller. The 6 bolts that are referring to pulls the power head right ? I have 2- 1/2" bolts, 2- allen head bolts and 2- 3/8" bolts. Did you have to pull lower shroud off too?
Seems like there should be easier way?

 

[engineerlutz]

Re: 7.5 Clinton Sea King - Troubles and Questions

I took the head off the cylinder and found a load of carbon build up. Clean it all off and screwed the head back on. Without the sparkplug, it turns freely and without too much effort. I put the plug in and it was a little better than before but was still really hard to turn on the compression stroke.

My friend decided it was time to give it a try. We put it all back together and and gave it a try. It started out pulling the same old way it used to but we got it going. It ran for about 1 minute and died, smoking terribly. I fiddled with the carb settings and we tried it again, choke off. It pulled easier this time and started 3rd pull. We shifted it in gear and fiddled with the carb a little more and it started running great.

My only concern is the water, or lack there of it's ejecting. I'm assuming that the impeller is just to cool the exhaust pipe. It is only trickling out the hole halfway up the engine leg.

What is a way to tell if the impeller is turning? Where should i see water being ejected? When i turn it by hand i can hear the impeller squeaking its way around.

I concluded it wasnt the gear box that was making it hard to turn. It still catches and pulls hard when i try to start it (likely from the broken tooth in the puller). After i got it running it seemed to loosen up and now pulls easier.

Thanks for the help.

My model has the 3 different pairs of the screws that hold the leg to the engine. It does seem like a lot of work just to replace the impeller. I hope i don't have to do it.

 

[Durlock]

Re: 7.5 Clinton Sea King - Troubles and Questions

I just bought a 7.5Hp Seaking made by Clinton for $50.00. Not sure of the year. Late 70's is my guess. Anyways, the previous owner says it ran perfect for him, but it has been sitting in his garage for 10 years. It looks to be in great shape! I haven't tried firing her up yet as I'd like to know what basic maintenance I should do before hand. I know next to nothing about OB's. Any advise would be greatly appreciated.

Model: K752 4106
Type: XTV52370A

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

Hi LXIX,

I'm also working to try to replace an impeller on K753 and having problem
getting to the impeller. If you pulled lower column off the power head, did you also have to replace the water plate to column gasket and other gaskets that power head rests on ?? Seems like it is lotta work just to replace impeller. The 6 bolts that are referring to pulls the power head right ? I have 2- 1/2" bolts, 2- allen head bolts and 2- 3/8" bolts. Did you have to pull lower shroud off too?
Seems like there should be easier way?

Let me start by saying that if there is an easier way, I havn't found it. When I pulled mine apart all the gaskets were in good shape so I reused the originals. However if you need gaskets go to your local Advance Auto Parts and spend $5.00 for a roll of rubber/paper gasket material and cut your own.

Yes the 6 bolts I refer to are to pull the power head from the L/U. I'm not sure what the allen head bolds are as I do not have them on my K751. I have 4-1/2 inch bolts and 2-3/8 inch on mine. Yes you will have to pull the lower shroud.

Keep in mind as I stated earlier when you do get to the impeller you may have to drill out the roll pin. I did at least. Use carbide or titanium bit. High speed steel is too soft.

Good luck with it if I can be of any more help just yell.

Brian

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

I took the head off the cylinder and found a load of carbon build up. Clean it all off and screwed the head back on. Without the sparkplug, it turns freely and without too much effort. I put the plug in and it was a little better than before but was still really hard to turn on the compression stroke.

My friend decided it was time to give it a try. We put it all back together and and gave it a try. It started out pulling the same old way it used to but we got it going. It ran for about 1 minute and died, smoking terribly. I fiddled with the carb settings and we tried it again, choke off. It pulled easier this time and started 3rd pull. We shifted it in gear and fiddled with the carb a little more and it started running great.

My only concern is the water, or lack there of it's ejecting. I'm assuming that the impeller is just to cool the exhaust pipe. It is only trickling out the hole halfway up the engine leg.

What is a way to tell if the impeller is turning? Where should i see water being ejected? When i turn it by hand i can hear the impeller squeaking its way around.

I concluded it wasnt the gear box that was making it hard to turn. It still catches and pulls hard when i try to start it (likely from the broken tooth in the puller). After i got it running it seemed to loosen up and now pulls easier.

Thanks for the help.

My model has the 3 different pairs of the screws that hold the leg to the engine. It does seem like a lot of work just to replace the impeller. I hope i don't have to do it.

See my post above regarding how to get to the impeller. In regards to the exhaust there will not be a stream or water "peeing" out like on other motors. Rather the manual states that a fine mist should come from the 6 exhaust holes on the L/U.

The way I tested my impeller was when I had the lower unit off the powerhead and the pulled the L/U apart, I took my drill and put the drive shaft in the chuck and tightened. Then I submerged it just under the waterline in a garbage can filled with water. Start the drill and see if water pumps out. If not it needs replaced. You can either use a long (1 1/2") Eska impeller of you can order one from the company. See my "Good News For Us Clinton Owners" thread.

Let me know if you need more info.

Brian

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

See below.

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

I just bought a 7.5Hp Seaking made by Clinton for $50.00. Not sure of the year. Late 70's is my guess. Anyways, the previous owner says it ran perfect for him, but it has been sitting in his garage for 10 years. It looks to be in great shape! I haven't tried firing her up yet as I'd like to know what basic maintenance I should do before hand. I know next to nothing about OB's. Any advise would be greatly appreciated.

Model: K752 4106
Type: XTV52370A

I have a K751 so I don't know the differences between the 2 motors but I'm guessing not much as they are both 7.5 hp. I would suggest removing the head and cleaning the carbon deposits from both the head and the top of the piston. While it is off take a look to make sure the cylinder walls are smooth. Change the spark plug.

I would also suggest doing a carb rebuild, I was able to get a rebuild kit from a local small engine shop for $10.50. BE CAREFUL WHEN RE-ASSEMBLING THE FLOAT BOWL. DO NOT TIGHTEN THE FLOAT BOWL SCREWS TOO HARD AS IT IS BRASS AND WILL STRIP THE THREADS! If you need the carb settings let me know I can give you what they are for the K751 they are prob close.

Check for spark, if you don't have any take some fine sand paper to the ignition system to clean your contacts. Make them real shiney!

Chances are real good if it has been sitting your impeller has dry-rotted. I would suggest changing it (see posts above for more detail).

I would change the L/U grease. There are 4 screws that hold a plate on the gearbox under the prop. If you have peanut butter looking lube it has water in it. Scoop it out and replace. You can either use Lubriplate (available at NAPA) or Mercury Marine Grease (which I opted to do, it's blue). After you replace the grease and get it out on the water pull the plate again and see if your grease is cloudy. If so you may need to replace your seals (about $5.00 each from Clinton) see my "Good News For Us Clinton Owners" thread.

Finally take the prop off and make sure the Shear Pin is in good shape. I took mine out on the water and my shear pin was broke and I wondered why my boat did not go anywhere........"idiot moment". Shear pins are easily made by going to Home Depot and buying a length of 3/16" brass rod. Cut it into 1.25" lengths and for about $4.00 you get a ton of shear pins. Keep a spare in the plug on the engine mount with a cotter pin so if you need to make a change on the water you have everything you need (except the plyers).

If I can be any more help let me know.

Brian

 

[Durlock]

Re: 7.5 Clinton Sea King - Troubles and Questions

Brian,

Will the impeller be more prone to dry rot then the rubber fuel hoses? Because those are still perfect. Would the fact that they're still fine after 10 years of storage be any indicator as to the condition of the impeller?

Thanks for the advice,

Jay

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

Jay,

I would say that the fuel hose condition is not an indication of the impeller condition. The reason being is even if they are made from the same material, the impeller is under greater stress than the fuel lines as it is a part that actually spins to push water. Being that it is a mechanical part and the fact that the fins on the impeller are much thinner in thickness than the wall of the fuel line I still would make it a point to at least inspect the impeller. The impeller fins are only about 1/16" thick.

My impeller when I inspected it, was missing 4 of the 8 fins and the ones that were still there were either cracked or deformed. I'm guessing it was original from the factory, or at least pretty darned old.

Even if the fuel lines "look" good, I would consider replacing them, neoprene hose is cheap and unless you cut your existing hose open there's no way of checking the interior condition of the hose. Especially if the fuel wasn't drained out of it before it was put up the last time.

When you get your motor running I would suggest when you are ready to call it a day, rather than pulling the choke to stop the engine (as reccomended on the decal, just close your fuel shut off valve and let the engine burn any remaining fuel that is in the bowl so you don't have any just sitting and getting stale before you take your motor out again. This might just be paranioa on my part but after putting as many hours in mine rebuilding it (please note I did start with a running motor), I'm trying to get into good habits.

I realize that I have advised putting a bit of work into your engine, this is what I did and let me explain myself. I got my engine and an inflatable boat together. While some of the things I have advised doing may not "need" to be done, I have done them as this motor is the primary source of propulsion for this boat. I don't want to get stuck with my 8 year old son on the water for what may amount to a "$.59 part".

Brian

 

[Durlock]

Re: 7.5 Clinton Sea King - Troubles and Questions

Ok, so I pulled the prop off and there's no shear pin. After removing prop, I removed bottom fin plate. The oil/grease inside is like muddy peanut butter. Beige and gray. It's gray around the propshaft seal. So that means the seal is bad right? It's been sitting in a guys garage for 10 years.

7.5 Sea king 1976-77

Model: K752 4106
Type: XTV52370A

Thanks,
Jay

 

[LXIX]

Re: 7.5 Clinton Sea King - Troubles and Questions

Jay,

The shear pin is an easy fix. Get some 3/16" brass rod (brass because it is soft and will break if you hit a rock or stump, rather than breaking your prop). Shear pins are (according to the manual) 1.25" in length. When you reassemble onto the propshaft, there should be a washer that goes on first, then the shear pin through the hole in the propshaft, then the prop, then the retaining nut with the cotter pin.

In regards to the seals, if I were you I would replace them (which is what I am doing, just waiting for them to arrive) just because they are so old, however to take the grease out you may need to pull the prop shaft (if you do, don't lose the bushings). There is a roll pin on the gear on the propshaft (once again you may have to drill it out). Remove the roll pin and it will allow the prop shaft to slide out giving you access to the entire cavity so you can wipe it down real well. If you don't mind tinkering, just remove the old grease and replace with new but inspect your gasket as that may be the culprit. Put it on the water and reinspect it when you get back home. if it's cloudy again replace the seals, if not, you are good to go. I'm guessing that Clinton has allocated for some water to enter the gear box as in the manual it says (This is the entire paragraph direct from the Clinton Manual regarding the gear housing).

GEAR HOUSING

The gear housing has been pre-lubricated at the factory. Check lubricant at least every twenty (20) operating hours as follows:

1. Be sure all water is drained from column then invert motor. Remove propeller and gear housing cap. The gear housing cap is retained by four screws.

2. Fill complete housing cavity with part 951-247 grease.

3. Replace gear housing cap, making sure the gasket between the cap and housing is not damaged. If the gasket is damaged replace with gasket number 94-386. Tighten (4) cap screws securely and install propeller.

Always remove old lubricant and replenish with new lubricant at the end of the outboard season or 75 hours of usage. This is important, as it removes any water from the gear housing and prevents possible corrosion or freezing to internal parts.

In regards to #2 I used Mercury Marine grease (available at NAPA). For the gaskets you can get some water proof gasket material and make your own.

Let me know if you need more help.

Brian