Max Speed 35 mph

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Husker
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Max Speed 35 mph

Unread post by Husker » July 4th, 2020, 2:43 pm

On today’s road test after rebuilding my transmission I drove the Jeep faster then I ever did before got to about 45 mph and it felt like it was surging.
Slow down to 30 and it’s fine for cruise around the neighborhood for the 15 min or so drive I did.

I set all my valves first to .017 then while running to .015

Set timing
Set carb with a tac dwell to 650 for my 660B emissions carb
(I have none of the emissions equipment)

I will be getting a vacuum gauge soon to check for vacuum leaks

As a precaution I retorqued my head bolts and intake manifold bolts per the TM

I have a spare 660b carb that I can mess with I know they only made 2 jet sizes do they have any mods that would help with this?

All my carb settings were with no choke and I drove with the choke all the way in this time which I wasn’t able to do before (it would stumble on acceleration) but after new correct sized fuel lines and better tuning it worked great
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

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rickf
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Re: Max Speed 35 mph

Unread post by rickf » July 4th, 2020, 3:51 pm

Set your idle mixture screw for best idle then back it out about a half turn and see if that takes care of the stumble. If not back it out another quarter turn. Changing the main jets will do nothing since these engines never run hard enough to use the full amount of gas from even the #28 jet. The exhaust manifold is far too restrictive to allow them to rev. That is one of the reasons they last so long. Opening up the mixture screw will richen up the midrange just enough to get rid of the flat spot. Is your timing set right on the mark and is you timing advance working in the distributor? Did you have that carb apart? If so did you check the float setting? Float setting on these is critical.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
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Re: Max Speed 35 mph

Unread post by Husker » July 4th, 2020, 4:28 pm

The float setting was set previously by 3 year ago me not nearly as good as today me is so I might have to look at that
Timing is set and I stripped and cleaned the distributor to get the advance weights moving right they were previously stuck
I will adjust that screw and see how it does then
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Husker
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Re: Max Speed 35 mph

Unread post by Husker » July 5th, 2020, 4:08 pm

Did that and then tested it seemed to get ride of the flat spot but I basiclly stall out on hills at lower speed uphill it surges bad and won’t stop until I adjusted the mixture back
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Mark
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Re: Max Speed 35 mph

Unread post by Mark » July 5th, 2020, 5:04 pm

Maybe try a different carburetor which is the basic cop out.LOL
mark


1968 m274A5
1960 m151
1981 m151A2
1964 m416
1971 m416

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rickf
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Re: Max Speed 35 mph

Unread post by rickf » July 5th, 2020, 5:11 pm

When you backed out the mixture screw how was it idling? Was it still smooth or was it stumbling? It is sounding like you are going to need to open up the carb and clean out the idle passages and set the float. When you are setting the idle mixture can you go from lean stumble to rich stumble and how much adjustment is there in between those two points? The reason I ask is a lot of times people will jam that idle screw down and that hogs out the metering hole and makes adjusting very hard and sometimes just not possible.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
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Re: Max Speed 35 mph

Unread post by Husker » July 5th, 2020, 5:46 pm

It was still idling goodish

now I can’t even get it back to wear it was with the tac dwell test two failed even harder with me unable to even drive it in the garage
Only other thing I can think of is possible fuel flow issues still but I don’t know

The carbs coming apart tomorrow I’ll try out my spare on the truck to and see how it goes....

I’m using ethanol free gas but it is kinda old but no real issues
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

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rickf
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Re: Max Speed 35 mph

Unread post by rickf » July 5th, 2020, 6:58 pm

That may be some of your issues. Old gas does not have to look old to give problems.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
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Re: Max Speed 35 mph

Unread post by Husker » July 5th, 2020, 7:00 pm

Yea that’s kind how I felt I have a full tank of it and a jerry can full.....

Maybe I’ll put it in my deuce and just get regular E85 from the station?
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

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rickf
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Re: Max Speed 35 mph

Unread post by rickf » July 5th, 2020, 8:27 pm

Never put E85 in anything other than an engine labeled specifically for it!! That is 85% alcohol!! You can run up to 10% ethanol in your engine with no problems other than some mileage penalty. Regular gasoline nowadays is allowed to have up to 10% ethanol.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
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Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Max Speed 35 mph

Unread post by Husker » July 5th, 2020, 9:19 pm

Yep poor wording tracking

10% ethanol pump fuel same I put in my TJ

Just got my spare carb apart it’s a 660A was in ok shape definitely was a straight take off had old fuel reside orange dust all in it orange accelerator diaphragm had to scrap off the bowl seal it was basicly just rotted out

Any issue with this over the B model I don’t recall if the consensus was that the early 660 series was a dude and they settled on the B model for all 151 generations


But if interest I suppose poored fuel from my jerry can into my sample jar to test the float and it does smell kinda stale so fresh gas may help but I don’t think it’s my root issue
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Husker
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Re: Max Speed 35 mph

Unread post by Husker » July 5th, 2020, 9:57 pm

With the spare carb all apart there is a vain that looks like part of the idle circuit I was trying to force fluid in it but it might be gummed up I have no idea how to remove it or where to try and send some air though it is brass only brass one of the 3 veins in the middle of the bowl
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

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rickf
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Re: Max Speed 35 mph

Unread post by rickf » July 6th, 2020, 10:11 am

Veins? You in the medical field by any chance? The idle jet is a in the bowl and will sometimes fall out of the bowl. You have to be careful of that. It is about in the center and has a small pointed section sticking up. This is the piece that clogs along with the passages in the main body where they exit in the throat of the carb just inside the intake flange. You can lay a couple boards on the bench and leave a gap between them and smack the bowl down on the boards to try to knock that jet lost but be careful that you don't deform the bowl and also watch that the jet has not com partially out before smacking it down again, I have destroyed more than one jet that way and they are getting hard to find. As far as whether the 660, A, B, are any better than the other the answer is no, they are all the same. very minor running revisions that really do nothing more than add price to the contract. The only real change in the 13660 series was the change in main jet size from #30 to #28 and like I said before you will never be able to fully use all the gas even the small jet can supply. That is only a function of wide open throttle. Flat spot is midrange.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
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Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Max Speed 35 mph

Unread post by Husker » July 6th, 2020, 11:06 am

Thanks rick I’ll give it a shot
It’s listed as just tube assembly item #36 in the diagram I have. an the TM says to replace it when removed

Other concern about this carb is the main tube that goes into the Venturi came off with just a slight pull. The -34 said this stays in the carb during the rebuild or at least made it seem that way giving if it measures bad you toss the whole carb in the trash!

Overnight soaked some of the grosser components in gas and the float is still good it remains floaty after siting all night.

I just need to flush out that last tube and I’ll feel good enough about slapping it back together with the new gaskets
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Max Speed 35 mph

Unread post by Husker » July 6th, 2020, 11:30 am

Rick you recommended on an older post perematex #2 for the bowl seal?
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

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