diff --git a/t/t2601-job-shell-standalone.t b/t/t2601-job-shell-standalone.t
index 29252ae623c7..67c5b14aa0f2 100755
--- a/t/t2601-job-shell-standalone.t
+++ b/t/t2601-job-shell-standalone.t
@@ -5,7 +5,7 @@ test_description='Test flux-shell in --standalone mode'
 . `dirname $0`/sharness.sh
 
 #  Run flux-shell under flux command to get correct paths
-FLUX_SHELL="run_timeout 60 flux ${FLUX_BUILD_DIR}/src/shell/flux-shell"
+FLUX_SHELL="run_timeout 300 flux ${FLUX_BUILD_DIR}/src/shell/flux-shell"
 
 PMI_INFO=${FLUX_BUILD_DIR}/src/common/libpmi/test_pmi_info
 KVSTEST=${FLUX_BUILD_DIR}/src/common/libpmi/test_kvstest
diff --git a/t/t2602-job-shell.t b/t/t2602-job-shell.t
index 0ecb8dc8142e..51d91b82aa41 100755
--- a/t/t2602-job-shell.t
+++ b/t/t2602-job-shell.t
@@ -184,30 +184,44 @@ test_expect_success LONGTEST 'job-shell: verify 10K line lptest output works' '
 	flux job attach -l $id >lptestXXL.out &&
 	test_cmp lptestXXL.exp lptestXXL.out
 '
+# N.B. sleepinf.sh and wait-event on job data to workaround
+# rare job startup race.  See #5210
+test_expect_success 'create helper job submission script' '
+	cat >sleepinf.sh <<-EOT &&
+	#!/bin/sh
+	echo "job started"
+	sleep inf
+	EOT
+	chmod +x sleepinf.sh
+'
 test_expect_success 'job-shell: test shell kill event handling' '
-	id=$(flux submit -n4 -N4 sleep 300) &&
-	flux job wait-event $id start &&
+	id=$(flux submit -n4 -N4 ./sleepinf.sh) &&
+	flux job wait-event -p guest.exec.eventlog $id shell.init &&
+	flux job wait-event -p guest.output $id data &&
 	flux job kill $id &&
 	flux job wait-event $id finish >kill1.finish.out &&
 	grep status=$((15+128<<8)) kill1.finish.out
 '
 test_expect_success 'job-shell: test shell kill event handling: SIGKILL' '
-	id=$(flux submit -n4 -N4 sleep 300) &&
-	flux job wait-event $id start &&
+	id=$(flux submit -n4 -N4 ./sleepinf.sh) &&
+	flux job wait-event -p guest.exec.eventlog $id shell.init &&
+	flux job wait-event -p guest.output $id data &&
 	flux job kill -s SIGKILL $id &&
 	flux job wait-event $id finish >kill2.finish.out &&
 	grep status=$((9+128<<8)) kill2.finish.out
 '
 test_expect_success 'job-shell: test shell kill event handling: numeric signal' '
-	id=$(flux submit -n4 -N4 sleep 300) &&
-	flux job wait-event $id start &&
+	id=$(flux submit -n4 -N4 ./sleepinf.sh) &&
+	flux job wait-event -p guest.exec.eventlog $id shell.init &&
+	flux job wait-event -p guest.output $id data &&
 	flux job kill -s 2 $id &&
 	flux job wait-event $id finish >kill3.finish.out &&
 	grep status=$((2+128<<8)) kill3.finish.out
 '
 test_expect_success 'job-shell: mangled shell kill event logged' '
-	id=$(flux submit -n4 -N4 sleep 300 | flux job id) &&
-	flux job wait-event $id start &&
+	id=$(flux submit -n4 -N4 ./sleepinf.sh | flux job id) &&
+	flux job wait-event -p guest.exec.eventlog $id shell.init &&
+	flux job wait-event -p guest.output $id data &&
 	flux event pub shell-${id}.kill "{}" &&
 	flux job kill ${id} &&
 	flux job wait-event -vt 1 $id finish >kill4.finish.out &&
@@ -216,8 +230,9 @@ test_expect_success 'job-shell: mangled shell kill event logged' '
 	grep "ignoring malformed event" kill4.log
 '
 test_expect_success 'job-shell: shell kill event: kill(2) failure logged' '
-	id=$(flux submit -n4 -N4 sleep 300 | flux job id) &&
-	flux job wait-event $id start &&
+	id=$(flux submit -n4 -N4 ./sleepinf.sh | flux job id) &&
+	flux job wait-event -p guest.exec.eventlog $id shell.init &&
+	flux job wait-event -p guest.output $id data &&
 	flux event pub shell-${id}.kill "{\"signum\":199}" &&
 	flux job kill ${id} &&
 	flux job wait-event $id finish >kill5.finish.out &&
diff --git a/t/t2611-debug-emulate.t b/t/t2611-debug-emulate.t
index 2d458aed8dc4..e9b50513b2cd 100755
--- a/t/t2611-debug-emulate.t
+++ b/t/t2611-debug-emulate.t
@@ -13,7 +13,7 @@ stop_tasks_test()     {
 
 test_under_flux 2
 
-TIMEOUT=10
+TIMEOUT=100
 
 parse_jobid() {
 	outfile=$1 &&
@@ -103,7 +103,7 @@ test_expect_success 'debugger: job attach --debug must not continue target' '
 	flux_job_attach ${jobid} jobid.out3 &&
 	tv_jobid=$(parse_totalview_jobid jobid.out3) &&
 	test ${tv_jobid} = "${jobid}" &&
-	test_must_fail flux job wait-event -vt ${TIMEOUT} ${jobid} finish &&
+	test_must_fail flux job wait-event -vt 2 ${jobid} finish &&
 	flux cancel ${jobid} &&
 	flux job wait-event -vt ${TIMEOUT} ${jobid} finish
 '