1975 850 Throttle Linkage Problem

[1960 Starflite]

I?m back with a throttle linkage problem on my 1975 850. For a little history on this engine, the boat/engine belonged to my Uncle and he took it to a marina a couple years ago because it was idling too fast. They got it to idle at a lower speed, but still high.

I bought the rig for the engine to mount on my pontoon. Now that I have the wiring replaced, carbs rebuilt and the water pump rebuilt, I am nearing the time to mount it. While placing the throttle linkage on the engine (control clamped in vice), I find that I can?t get the linkage to push the distributor against the idle screw. The picture of the engine linkage is as it came back from the marina. So I thought ?I?ll adjust the inner cable? like on my old 1963 650, WRONG, looks like the inner cable is held in place by some kind of swedge/clamp, no set screw like the old style. So I pulled the control apart thinking I can adjust the barrel on the threaded anchor, WRONG again, the barrel is also somehow permanently mounted to the outer cable. Both of the barrels (throttle and shift) are one inch from the outer cable housing. Both cables are the same length and have the same travel.

I am now at a loss on this; can someone guide me in the solution to this problem? Sorry for the long post, but wanted to include as much information as I could.

Thanks, Tom on Buckeye Lake

 

[ShowMeGuy]

Re: 1975 850 Throttle Linkage Problem

I'll take some pics of my 1973 tonight. I have about all the case off of it along with all accessories with the exception of the distributor and cables.
Not sure they will work or help but I haven't touched mine and not planning on it until I receive my SM.

 

[merc850]

Re: 1975 850 Throttle Linkage Problem

I had the same problem after replacing the trigger with an aftermarket one, the solution was to retard the spark by moving the distributor pulley one notch CCW on the beltbut before you do this check the timing according to this page.
This also means resetting the throttle pick-up and max spark advance.

 

[1960 Starflite]

Re: 1975 850 Throttle Linkage Problem

Thanks merc850. I was thinking the same thing, that the timing may be advanced too far at idle. The engine is on a stand inside my garage. I have to get a couple of young, big fellows to move the engine/stand outside so I can run the engine on muffs. It may be OK at this point as I broke the old belt when removing the flywheel to replace stator. I installed the new belt with the 3 dots aligned to pulley arrow and crankshaft centerline. I'll put the timing light on it and see where the advance is. May be a while as I can't move this thing myself. I did start the engine (lower unit removed) but only for a few seconds just to see if it would run.

 

[Chris1956]

Re: 1975 850 Throttle Linkage Problem

Some of those early distributors had an adjustment on the side, that might help. C/O ShowMe's post that I responded to today. Do you have that adjustment under the zerc fitting on the port side of the distributor?

If not, check the installation of the timing belt and the positioning of the timing pointer, if you have one.

 

[1960 Starflite]

Re: 1975 850 Throttle Linkage Problem

Chris, My 850 doesn't have the adjustable distributor link. I saw the ShowMe post and noticed that. I pulled out my box of old 650 parts, looking for the adjustable link, found it but it's way too short to fit my 1975 850. Several differences between the 1973 and 1975's, IE: Distributor link, fuel filter after pump (not in carbs), fuel line fittings barbed instead of ferrels with compression nuts. Mine does have the timing pointer and I will be checking the timing when I get the engine outside.

Thanks to all for the suggestions, What a great forum !!!!

Tom on Buckeye Lake

 

[Chris1956]

Re: 1975 850 Throttle Linkage Problem

Ok, Use an accurate measuring device to set timing pointer exactly at TDC. Maybe that will fix it.

 

[1960 Starflite]

Re: 1975 850 Throttle Linkage Problem

Ok, Use an accurate measuring device to set timing pointer exactly at TDC. Maybe that will fix it.

Chris, already did that with a dial indiacater on number 1.

Got the beast drug outside yesterday, hooked up muffs, pumped up bulb, hit choke button while cranking, "can you flood". Moved warm up lever to full, cranked 20 seconds without choke and it started. Let it run a couple of minutes, just above idle to warm up. Got my long skinny screw driver out to adjust mixture screws. "can you say flood" again? Fuel is running out of both carbs, guess I'll pull the float covers and try again. I have done carb jobs on my 300 and 650 without a problem like this. Didn't get to the timing part.

 

[Chris1956]

Re: 1975 850 Throttle Linkage Problem

Side bowl carbs, right? Invert the carb covers and set levers to be straight across. Adjust by bending lower (or inside) lever (long straight one with 1/2 round hook). Now set cover upright. Measure between two levers. Should be max of 1/4". Bend l-shaped leg of bottom lever to achieve this. Spring on top of float is intact? Float is not partially disolved (foam) or cracked (hard plastic)? Inlet needle and seat are in good condition?

 

[merc850]

Re: 1975 850 Throttle Linkage Problem

You have to adjust the screws while running under load (on the boat) at about 1100 rpm.

 

[1960 Starflite]

Re: 1975 850 Throttle Linkage Problem

Was the site down or was it just my computer?

Anyway, I pulled the float covers and I had the float level set too high, fuel coming out of the ventura tubes when bulb pumped up.

Moving on, I put the timing light on it and noticed that #1 was firing 5 degrees AFTER TDC. Reset belt one tooth, now when the distributor is against the throttle stop the timing is 3 degrees BTDC, but it is idleing way too fast, round 1200 rpm. I see in the manual "advance timing to 3-5 degrees BTDC and move the cam on the distributor to just contact the carbs" (my wording here). That is where things are set now, and the idle is way too high.

Now I got to thinking (bad on me), that maybe to get the idle lower, the timing must be around TDC at idle. But I can't do that because of the oridgnal problem in post one. Now do I pull the belt again and retard the timing there, so I can have a better chance of setting the idle stop screw? I hope that made some kind of since to you folks here.

Thanks for the help
Tom on Buckeye Lake

 

[Chris1956]

Re: 1975 850 Throttle Linkage Problem

Carbs should just be ready to open at 4-6* BTDC, however, throttle cable and idle stop screw should be set to allow throttle cable to push distributor down to near TDC. It would be normal to idle at TDC or near it. Just make sure carbs do not open until timing is 4-6* BTDC.

 

[1960 Starflite]

Re: 1975 850 Throttle Linkage Problem

Carbs should just be ready to open at 4-6* BTDC, however, throttle cable and idle stop screw should be set to allow throttle cable to push distributor down to near TDC. It would be normal to idle at TDC or near it. Just make sure carbs do not open until timing is 4-6* BTDC.

I retarded the timing by moving the pulley one tooth again. (now that I understand just where the timing should be at idle). I was able to adjust the barrel on the cable so that I now have enough travel to get it to the throttle stop. I do see that I now need to adjust the cam on the distributor to touch the throttle lever at 4 degrees BTDC. I'm learning, hope I can retain the information in my old brain.

Thanks, Tom on Buckeye Lake