35 hp RPM

[pikefisherman]

Motor dos'ent seem to get very high RPM when running full throttle this is photo of linkage at full throttle. Motor is not running in photo.

 

[Frank Acampora]

Re: 35 hp RPM

That's because you are not reaching full throttle. The cam should travel far enough so that the scribed line at the end is tangent to the black roller.

Either the connecting rod is set too short or the wrong hole in the control box arm was used, resulting in reduced travel. I can see in the photo that both ball links are run all the way down the threads in the connecting rod. It is too short. Adjust both ball links so that the cam is positioned correctly on the black roller at wide open throttle.

 

[pikefisherman]

Re: 35 hp RPM

Thanks: I will check it out, but it may be a few days, we are going to have crappy weather here the next few days. Can I remove the prop and run on full throttle without hurting motor or should I just adjust connecting rod. If I understand you correct I adjust rod until the red in photo is in the middle of roller?

 

[Frank Acampora]

Re: 35 hp RPM

OH NO! Don't remove the prop and don't run at full throttle in the driveway. Just set the rod and see what happens on the water. IF the idle speed is too high, lower it by unthreading the idle stop screw on the side of the linkage. Probably located on the side of the exhaust cover.

 

[pikefisherman]

Re: 35 hp RPM

Ten Four on the running with no prop, I do have motor in water barrel, so if I adjust the rod, I may need to adjust idle screw, it seems to idel a little fast now. It may be a few weeks before I can dunk it in the water again, because of ice, again thank you for the help!

 

[oldboat1]

Re: 35 hp RPM

while the ice is melting, remove the throttle quick release at the engine and move the linkage by hand to open the throttle -- should tell you where the connector should be when the throttle is open. There are a couple of different quick releases, one longer than the other. Look and see what one is on the shift linkage -- might have them switched around. You can tweak the overall length of the cable by screwing down the connector (or the other direction to lengthen), but if that connector is the wrong one (too long), chances are you won't be able to shorten it enough. Were these on the original remote control cables? Changed out at some point? (some Ebay vendors show both lengths in hawking the connectors), to give you an idea of the difference -- also probably shown in a manual somewhere for the remote. Afraid I don't recall the various applications.

(note -- would need to put the motor in gear to open the throttle. don't need to run, but don't force the shift. bump the prop or flywheel a little to allow you to put it in gear.)

btw -- strikes me I may have the push-pull cable operation backwards for throttle (thinking it was pull to advance, but might be opposite.) Suggestions still stand -- pull quick release from throttle cable and operate throttle by hand to see what the throttle travel is (each way) to determine proper location of connector for remote cable -- also the point about the difference in connectors. Sorry if description confusing, though.

 

[jerryjerry05]

Re: 35 hp RPM

Another thing to consider when your motor won't get to max revs.

The prop you have might not be right for the load or boat size.
What boat and prop?
Too much in the boat?
Too many people and too many coolers and "STUFF"??

 

[pikefisherman]

Re: 35 hp RPM

Thanks all: As I posted a 35hp on a 20foot pontoon, I'm not looking to set a speed record, it just seems that the motor could come up maybe another 2k.I think Frank Acampora has the right idea.

 

[jerryjerry05]

Re: 35 hp RPM

Didn't see anywhere you posted it's on a pontoon.
If it came original on the pontoon then you probably have the right prop.
If it's added later? Then the pitch is probably wrong?
What pitch on the prop you're using?

 

[MickLovin]

Re: 35 hp RPM

Thanks: I will check it out, but it may be a few days, we are going to have crappy weather here the next few days. Can I remove the prop and run on full throttle without hurting motor or should I just adjust connecting rod. If I understand you correct I adjust rod until the red in photo is in the middle of roller?
View attachment 227435

They actually had test props for testing at WOT, unsure if Chrysler ever used them. The test props were weighted I think to put a load on the motor. Does that sound correct Frank?

 

[pikefisherman]

Re: 35 hp RPM

jerryjerrt05:If I may ask how do I find out the pitch on prop? Always wanting to learn new things thanks.

 

[MickLovin]

Re: 35 hp RPM

I am not jerryjerry but there is usually a number stamped into the prop, you need to find that and I would just google it, but sometime the number will tell you for e.g I had a 528-23, it was a 23" pitch prop, I also have a I think a 511-21 this was a 21 " pitch s/s prop. Not sure if that is the same for other props, but may be an indication.
May I ask were you successful in adjusting the throttle linkage? As this may be the only problem you have, if the motor came with the pontoon, it may already be pitched right, let us know anyway what it's pitch is if you can find the number on it, or just let us know the number and I will source what size it is for you.

 

[oldboat1]

Re: 35 hp RPM

Can quick connector post be relocated inboard of the one shown in the pic? would effectively extend the reach of the remote cable in opening throttle. Possible adjustment at the box (Frank A's #2 post), or at the motor. I just worked on my Sailor last night, and adjusted one at the box (shift cable) and one at the motor (throttle cable -- mine has two holes for the post).

 

[Frank Acampora]

Re: 35 hp RPM

People: Look at the photo again! The two ball links are screwed as far in as they can go. THIS IS INCORRECT! A simple adjustment of the two ball links to lengthen the rod is all that is needed to allow full opening of the carb butterfly. As it stands now he is getting only 1/4 to 1/2 opening, thus limiting RPM as surely as if he were only running at partial throttle. (which he is)

 

[pikefisherman]

Re: 35 hp RPM

Thanks for the tons of help, as stated, the weather has been just nasty in Mich. I will check things out over the weekend and let you guys know I think Frank Acampora has the right idea. I don't know if the motor came with pontoon but I think so. I did see numbers on end of prop so I'll check it out. Might be a good idea to have a spare as it is just held on with a nut and cotter pin.

 

[oldboat1]

Re: 35 hp RPM

Frank -- do believe we are looking at the same pic, but different suggestions. Think the best approach is simply to take off the remote cable quick release, and manually see where the travel is. If it's that connecting rod, problem should be apparent. Likewise if the remote cable needs to be adjusted. (btw pike, weather can't be much worse there than up here. almost spring, though.)

 

[MickLovin]

Re: 35 hp RPM

People: Look at the photo again! The two ball links are screwed as far in as they can go. THIS IS INCORRECT! A simple adjustment of the two ball links to lengthen the rod is all that is needed to allow full opening of the carb butterfly. As it stands now he is getting only 1/4 to 1/2 opening, thus limiting RPM as surely as if he were only running at partial throttle. (which he is)

Totally agree Frank, his first concern is throttle linkage adjustment and having the motor running correctly, before worrying about his prop pitch.

 

[MickLovin]

Re: 35 hp RPM

Wouldn't it be a matter of putting the remote to WOT and checking his butterflies?

 

[Frank Acampora]

Re: 35 hp RPM

I hate to belabor the point, BUT--There is no high speed stop on the control box, therefore the handle and thus the control cable, will move as far as the engine lets it. There is, however, a high speed stop on the engine linkage to limit timing advance. Because of this stop, even with the cable quick-connect removed, the cam will advance by hand only to the point where it is now. It is OBVIOUS from the photo that the linkage rod is too short and the cam is not opening the carb butterfly fully. Once the OP adjusts the ball links and rod so that the scribed line touches the roller correctly, the engine will gain RPM. THEN he can worry about if it has the correct prop for a 'toon.

Because of the design, the length of the threaded end of the throttle cable has no relation to performance EXCEPT (in this case) to adjust the quick-connect so that about 1/4 inch is pulled out in neutral. This allows the engine to shift into gear before timing, throttle, and RPM start to advance

Of course, since I can not see the carb and don't know if the butterfly IS opening fully due to a previous maladjustment, and I don't know if it is the correct carb, the above only applies if it IS the stock carb and all other links are correctly adjusted.


I could be wrong: I was wrong once---I THOUGHT I was wrong but was really right! LOL

 

[MickLovin]

Re: 35 hp RPM

So the handle doesn't have a stop at the Fast mark, wouldn't the motor not idle properly in the idle position? I can see what you are saying about the throttle linkage it is wound right in at both ends and it looks like the cam needs to hit the first up-step from the red marker. May I ask Frank and I don't mean to hijack the thread, is the set-up of the red mark the same as we do on the 3 & 4 cyl engines, where it needs to just touch the roller centre? From there how would he set the idle on this, sorry I am unfamiliar with the 2 cyl set-up, as it would be incorrectly set-up at the moment? Do you actually set the timing up by a voltmeter at WOT or do you have to do the 2 cylinders by timing light?