Old Mitts and Merril Chipper vacuum leak?

[M&M Chipper]

Hello folks, I am new here and I have a question. I am retired after breaking my spine at work. I do mycology as a hobby now and purchased an old Mitts and Merril drum chipper to supply myself with endless woodchips.

The chipper has the industrial Ford 6 cylinder motor. Not sure what year the chipper is, guessing 1960-1970's. It runs excellent, starts right up, revs up quickly, idles smooth, engine does not shake at all. The problem is that when the motor is rev'd to high RPM for engaging the drum, it begins to rev up and down...over and over....like it has a major vacuum leak. Upon inspection I found there's a fitting on the left side of the carbuetor that is sucking air in. I have no idea what is supposed to be attached there...I see no fallen lines or any thing to connect to this fitting. When I hold my finger over the hole the up and down loping rev doesn't stop. This chipper has a manual choke.


I was wondering if any of you fellas might own this type of chipper and be able to take a look and tell me what is supposed to be hooked to the carb on the left side fitting. I really need my chipper working this spring, any help would be greatly appreciated. Thanks so much everyone I am hoping someone here can help me.



M&M Chipper

 

[DUGs-sawshop]

Is the motor turning the correct RPM ? Probably hard to know the manufacturers suggested RPM , but worth finding out. Thinking it may be on the rev limiter or have a misadujted governor. Good luck with it.

 

[M&M Chipper]

Thanks for the reply.


It doesn't have a tachometer on it, but guessing it was running about 3000-3500 rpm wide open with the drum spinning. It does seem that the motor wasn't revving as high as it used to when wide open. The discharge chute would clog up easier.... I'm guessing because of the lower RPM's.


Maybe I should inspect the throttle. The original one was broken and now it has a "T" handle that must be kept in desired position with vice grips. This isn't something I've done...I purchased the chipper with the throttle in this condition a year ago for a decent price.

But that could be part of the problem I suppose not high enough RPM's due to worn out throttle cable.

There's still the hole sucking air in the side of the carb, still hoping someone here has one of these chippers and we can compare notes.


Thanks again everyone.

 

[rarefish383]

Our old Asplundh 16 in drum had a Ford 300 six cylinder. It's a very simple and easy to work on engine. I'd find a local mechanic that was around when they still had carbs and let him have a go at it. I'd just block off the vacum leak to start with. As some one else said, it could be a govenor problem? With the quality of fuel nowadays and if the machine gets low use you may need to clean or rebuild the carb, they gum up quickley. Good luck , Joe.

 

[M&M Chipper]

Thanks again for the reply.

It's a really nice day out so I was planning to try a few things. Will block off the vacuum leak plus see if there's any slack in the throttle line and try to rev it up again and see if it helps any.

Just thought it was pretty odd how perfectly it runs and has ran over the past year. Has to be something pretty simple you'd expect.


Thanks again for the advice.

 

[treevet]

I had a '75 Mitts 16" throat with that engine for about 25 years. The 16" is superior to the 12" IMO. Great chippers though, many staggered knives so smaller chips and more to a truckload and better deadwood pulling and slower duck necessary on the "chuck and duck" aspect. Double sided knives. Karl Kummerling in Massilon Ohio still sells them and may offer some advice.

 

[treemandan]

Is it getting enough fuel? Check the system reall good. The tank may be dirty. If it has a governer the lack of fuel could cause this problem.

 

[M&M Chipper]

!

Thanks for the input!


Yea, weak fuel supply would cause these symptoms, it has one of those external filter/fuel pump all in one deal. I will check the filter tomorrow and the fuel stream, but it starts easy, rev's up fine, just cannot sustain the rev without loping.


I looked today and it has a Carter carb...I was trying to see what model the air pump that seems to control the automatic chipper throttle is (some strange linkages). It's connected to the carb and is supplied power from the alternator via a belt.

The throttle and choke levers were sticking a bit so I oil'd em up today, everything moves much easier. I also oil'd up the many linkages going to the carb. It has an oil bath type air filter just to let ya'll know.

Tomorrow I will recheck all sugestions and try it again. Really appreaciate the help, getting behind as we speak.

 

[treemandan]

Look in the gas tank, check pick - up tube. That thing you are talking about is the governer.

 

[M&M Chipper]

The governor looks pretty old and complicated. Sure hope that's not the problem as it'd probably be pretty hard to find a replacement.


I knew about Karl Kummerling (sp?) was going to call them as a last resort if I cannot fix it myself.

Guess I left the key on, now the battery needs charged.....always something.


Have a great Easter everyone.

 

[treevet]

The gas guage often stops operating in those old chippers and how did they check the gas?

The dirtiest bark falling off stick laying on the side of the road dunked in the tank .....if it is not their own chipper.

 

[Rftreeman]

probably something with the governor, if it runs fine and speeds up under a load like it should then I would worry to much about it....

 

[M&M Chipper]

If this chipper had the original tank I'd be there with ya guys....but it has a new fuel cell and it's very clean inside so pretty sure it's not a clog.

A mechanic for the metro bus service in St Louis owned this chipper before me and did an excellent job with rebuilding the whole unit. Most things appear new or rebuilt on this chipper. It came with several new oil filters and other new parts. One of the best looking 35 year old chippers you'll run into.

I am pretty sure that the problem is something simple, probably something with the governor. Just hope I can figure it out in time to get some work done.



On a side note, had some shiitake mushrooms start showing up on some logs we made last spring. Never had a fresh shiitake, hope they're good. It's pretty easy to make logs, but want to use bags of chips when I get it fix'd.


I might try to take a few pictures of it so ya'll can see the beast I am working with.


Thanks all!


M & M chipper

 

[treevet]

35 yrs old would put it at a 1975 which I owned for 25 years. Is it a 16 or 12 inch?

 

[gdavis24]

Governor speed

That metal lump with belts on the front and arms to the carb is a governor, designed to keep rpm constant in response to load fed in chipper from time to time. Your throttle cable that sets the base speed prob attaches there, and not to the carb, right? Check that the mounting points of throttle cable inside and outside sheath have not moved. Governor also needs oil inside...bolt on side is a drain level hole, bolt on top is a filler hole.
Many of those 40 yr old governors were supplied by HOOF company im the midwest, which is now owned by piercelockcraft.com in Upland IN.
Good luck with your machine.

 

[Kogafortwo]

vacuum advance for distributor?

I am speaking from old-school automotive work here. Never worked on a larger goverened industrial engine.

But the old mechanical distributors did have a vacuum hose from somewhere in the manifold / intake system to advance the spark based on load~vacuum.

But it sounds like everybody has you on track for the governor. So ignore my advice, unless of course you're working on a 1973 Country Squire station wagon with the 400 cube Cleveland motor.

 

[M&M Chipper]

It's the 16" chipper. Makes really small chips when running properly. Been raining so I haven't got to work on it yet.


It worked great last summer, don't know what could have happened to make it lope at high, sustained RPM.


It was very well taken care of before I purchased it. Sure it's something small that I'm missing.

 

[M&M Chipper]

That metal lump with belts on the front and arms to the carb is a governor, designed to keep rpm constant in response to load fed in chipper from time to time. Your throttle cable that sets the base speed prob attaches there, and not to the carb, right? Check that the mounting points of throttle cable inside and outside sheath have not moved. Governor also needs oil inside...bolt on side is a drain level hole, bolt on top is a filler hole.
Many of those 40 yr old governors were supplied by HOOF company im the midwest, which is now owned by piercelockcraft.com in Upland IN.
Good luck with your machine.

Thanks much! Yes, it's a HOOF governor and I checked the throttle cable and it's getting a full pull. I will check the oil level tomorrow. I'm guessing regular motor oil goes in. Thanks again for the info.