Cherokee 4WD V6-173 2.8L VIN W 2-bbl (1985)
Idle Speed: By Symptom
Technical Service Bulletin # 000770
Date: 850801
Carburetor - Engine Surge at Cruising Speeds
AUGUST 1985 000 770
1985 CHEROKEE/ WAGONEER 70 SERIES
6E
ENGINES
Attention: Workshop, Parts Department
MODEL 2SE CARBURETOR DIAGNOSIS AND ADJUSTMENT
The Model 2SE carburetor on some 1985, 70 Series models, may require adjustment to eliminate surge at cruising speeds and/or a hesitation when
accelerating at 1/2 to 3/4 throttle. Carburetors that may require adjustment were used on 1985, 49-State, 70 Series models built prior to April 15, 1985,
and equipped with a V-6 engine and automatic transmission.
Diagnosis and adjustment procedures are as follows:
DIAGNOSIS
1.
Inspect the fuel return line at the fuel pump. See if a fuel flow restrictor has been installed in the return line as described in M.R. 244 I.S. Note
32E. Install a fuel flow restrictor if necessary.
2.
Road test the vehicle and note performance. If surging occurs while cruising at 35-45 mph after torque converter lockup, and/or a hesitation occurs
when accelerating at 1/2 to 3/4 throttle, with engine at end of warmup period, proceed to next step. If some other performance problem is noted,
further diagnosis will be necessary.
3.
If surge was noted during the road test, proceed to Adjustment Procedure 1.. If hesitation was noted during the road test, proceed to Adjustment
procedure 2. However, if both conditions were noted, perform Adjustment Procedures 1 and 2.
Adjustment Procedure No. 1.
1.
Remove the carburetor as outlined on page B-214 of the M.R. 244.
2.
Remove the air horn and air horn gasket.
CHANNEL RESTRICTION LOCATION
3.
Increase the diameter of the channel restriction (A) in the float bowl with a 1.15 mm drill bit J-35821 (see illustration). Use finger pressure only to
rotate the drill through the channel restriction.
CAUTION: Use only the specified drill size to increase the diameter of restriction (A). Do not use a drill motor to operate the drill bit. Use finger
pressure only.
4.
Adjust float level (dry) to 3.175 mm - to - 4.191 mm (0.125 in - to - 0.165 in.). Refer to M.R. 244 pages B-194 and B-195 for procedure.
5.
Reassemble and install the carburetor.
6.
Adjust carburetor idle mixture as outlined on pages B-207 through B-211 of the M.R. 244.
7.
Adjust engine idle speed as outlined on pages B-202 and B-203 of the M.R. 244.
8.
Adjust the automatic transmission throttle cable.
