compression for 1980 15hp

[badbrad1m]

Does anyone know what the cranking compression should be for a 1980 15 hp/E15RCSD motor be?

This motor has not been run for a few years and the throttle shaft appears to be seized and won't rotate. A few small hole were drilled in the housing above the shaft and WD40'd a few times but it won't budge much. Any ideas how to dissolve this obvious corrosion, or will the powerhead have to be removed to remove the throttle shaft?

Thanks!

 

[JustJason]

Re: compression for 1980 15hp

i assume you disconected the throttle linkage to the carb...
Carb throttle plates/shafts/shaft-seals etc are non-serviceable items.

If the shaft is frozen/sticky you need a new carb.
If you did drill holes you need a new carb.

 

[JustJason]

Re: compression for 1980 15hp

oh... 100psi minimun

 

[iwombat]

Re: compression for 1980 15hp

Where exactly are the holes drilled? The carb is probably toast. But, the most likely reason that shaft is stuck is that the carb was overtorqued onto the powerhead and the carb body was warped. They can sometimes be brought back, but not after they've been drilled on.

 

[JustJason]

Re: compression for 1980 15hp

oh... 100psi minimun

 

[badbrad1m]

Re: compression for 1980 15hp

Where exactly are the holes drilled? The carb is probably toast. But, the most likely reason that shaft is stuck is that the carb was overtorqued onto the powerhead and the carb body was warped. Then can sometimes be brought back, but not after they've been drilled on.

No, you misunderstood. I didn't drill the carburettor shaft. The tiller handle connects to a short 4-5" shaft in the motor body. The shaft has a geared head on it that turns the throttle linkage up under the flywheel. Is is the shaft connected to the twist-grip throttle that is seized in the motor housing.

Anyone ever find this seized in a motor that hasn't been run for a long time?

As far as compression - anyone have a specification? I know the cylinders should be within 5% of each other, but what range should the compression be?

Thanks!

 

[iwombat]

Re: compression for 1980 15hp

Yep, I totally misunderstood. Could be that your timer base is all bound up -- not an uncommon problem. You'll have to pull the flywheel and inspect, but timer plates do need lubrication every now and again or they'll bind up. There's no easy fix for this besides disassembly and inspection.

(Ain't that the truth for most things though?)

 

[JustJason]

Re: compression for 1980 15hp

doh!!!
Disconnect the linkage where it comes in through the pan.
That will tell you if your bind is in the handle or the motor.

compression is 100psi minimum

 

[badbrad1m]

Re: compression for 1980 15hp

doh!!!
Disconnect the linkage where it comes in through the pan.
That will tell you if your bind is in the handle or the motor.

compression is 100psi minimum

Thanks, the timer base does move - it is the throttle/tiller shaft that is seized in the housing. Anyone know anything better than WD40 to free a seized/corroded shaft? Does the power head have to come out to get this shaft out?

100psi is the min, what would be the max I should expect?

Thanks!

 

[Rick.]

Re: compression for 1980 15hp

The tiller handle comes apart rather easily. You should take it apart and clean the parts rather than spraying them with wd40. On re-assembly you can use some lubricant ( grease) to keep things moving smooth. When I first removed mine I was amazed how much sand and dirt was in the throttle/tiller arm.

You may want to keep cleaning parts right up to the timing plate. Clean parts, well lubricated, is the way to go rather than WD40. Have fun. Rick.

 

[badbrad1m]

Re: compression for 1980 15hp

The tiller handle comes apart rather easily. You should take it apart and clean the parts rather than spraying them with wd40. On re-assembly you can use some lubricant ( grease) to keep things moving smooth. When I first removed mine I was amazed how much sand and dirt was in the throttle/tiller arm.

You may want to keep cleaning parts right up to the timing plate. Clean parts, well lubricated, is the way to go rather than WD40. Have fun. Rick.

Thanks Rick, it is the shaft at the end of the tiller handle that goes into the motor housing (it has a gear on the other end). That is the shaft I'm talking about - not the tiller handle. Can you get this shaft out without taking the powerhead out? Thanks!

 

[JustJason]

Re: compression for 1980 15hp

if your sporting more than say... 160+ you may have a little to much carbon buildup.
PB Blaster is just about the best penetrant there is. (errr... haven't found one better yet!!)

 

[iwombat]

Re: compression for 1980 15hp

If my memory serves - yes. It rests in a bracket bolted to the powerhead. I think you need to pull the flywheel to get access to the mounting points.

And, my corrosion buster of choice is diesel and ATF fluid. There are many other equally acceptable choices.

Pull the flywheel, and maybe even the timing plate and you'll get access to that shaft I think.

 

[JustJason]

Re: compression for 1980 15hp

and when you put it all back together use Mercury 24C or special lube 101

 

[Rick.]

Re: compression for 1980 15hp

Sorry but my manual is at the lake 300 miles away from here. I think you can remove the part your looking at by removing a spring C-clip but I just don't remember. One thing to be aware of is that you need to line up the gears your trying to remove with the vertical throttle shaft that comes off it. (Vertically) I was never able to get my idle adjustment to work on my 15 HP. Tried to post it several times and got no usable help. Then one day I was going over the manual and it talked about some marks that need to be aligned when re-installing the part your trying to remove. I got the flashlight out and sure enough the vertical shaft was one tooth out keeping it well clear of the idle adjustment push rod. Funny thing is it never effected the motors performance. Just couldn't adjust the idle speed which was a real pain for trolling. Best of luck. I can get a manual from a friend so let me know if you still need help and I'll try tonight. Rick.