Engine RPMs goes up but no trust on the propeller after removing a sucked rope

[JC Chile]

Problem: the engine runs fine, and RPM goes up but the propel is not providing propulsion. It seems like a gear issue…where should I start?

I have a single engine 2018 AR195, I bought it with about 80 engine hours. Shipped home (Chile in South America) and on my second day on the lake, it got a sky rope wrapped around the shaft (I know….). I didn’t realize about it, so I sucked the rope all the way until the engine stalled by itself.

I was pulled to the dock and took the boat out of the water and took all the rope out of the shaft.

I launched the boat back in the water, the engine seams to run perfect but the power is not being transfer to the propeller. Making several tests in one or 2 timescthe propel gain trust and the boat worked normally. But most of the tests I did, the engine RPMs goes up but no trust on the propeller.

I removed the propel and shaft out of the housing to make sure that the propeller and the shaft are clean and in good conditions and everything seems to be fine.

I detached thee shaft to check the treads threads thinking that the torque made by the engine and the sucked rope could have damaged it but it looks fine.


Not sure what else could be causing this problem of lack of propulsion from the jet when the engine is accelerating well, and the revs are going up but no trust in the propeller.


Need the community’s help!

 

[WREKS]

It seems like there is still a piece of debris in the pump housing.

 

[84rzv500r]

it is possible tho not likely that the shaft broke or the splines stripped however you indicate these look good
are there bubbles in the jet stream idling in the water?
does the midbearing seal drip or leak water into the engine bay when setting in the water?
check the cleanout plug is secure and the seal is not damaged...
check the pump is completely clear
inspect the stator housing veins aft of the impeller for damage (missing chunks or missing all together
check the clearance with a feeler gauge between the impeller and the wear ring...
check the sealant in the pump tunnel seams for torn or loose pieces
make sure the reverse gate is opening...

if you dont have a service manual get one...

thats all i can think of off the top of my head...

 

[Julian]

Did you put the clean out plug all the way back in? If so, I'd pull the pump off the back to look for additional stuff wrapped around the shaft. Should take you 15 minutes to do, and is very easy (5 bolts and one quick release on the reverse gate).

 

[Ronnie]

Does the throttle arm on your boat have a large button at the joint / connection point to the throttle assembly which engages and disengaged the forward and reverse bucket (so you can rev up the engine without putting the boat in gear so to speak)? See the black disc in the attached pic. Also make sure that the control rod is attached to the top of the bucket.

 

[JC Chile]

It seems like there is still a piece of debris in the pump housing.

I detached the impeller and shaft and it's all clean. no left debris. Thanks!

 

[Murf'n'surf]

Need pics of the pump and impeller to diagnose better. Take pics looking into the pump with the hood in full forward.

Seems likely that you bent the impeller blades slightly or you caused damage to the wear ring.

 

[JC Chile]

it is possible tho not likely that the shaft broke or the splines stripped however you indicate these look good
are there bubbles in the jet stream idling in the water?
does the midbearing seal drip or leak water into the engine bay when setting in the water?
check the cleanout plug is secure and the seal is not damaged...
check the pump is completely clear
inspect the stator housing veins aft of the impeller for damage (missing chunks or missing all together
check the clearance with a feeler gauge between the impeller and the wear ring...
check the sealant in the pump tunnel seams for torn or loose pieces
make sure the reverse gate is opening...

if you dont have a service manual get one...

thats all i can think of off the top of my head...

Thank you so much, great list of recommendations...I will do it and get back to share how it goes. I don't have a service manual, will get one!

 

[JC Chile]

Need pics of the pump and impeller to diagnose better. Take pics looking into the pump with the hood in full forward.

Seems likely that you bent the impeller blades slightly or you caused damage to the wear ring.

yes, there is some damage on the impeller but it didt seams to bi that big. i will take better pics to share but this is what i have now

 

[JC Chile]

Does the throttle arm on your boat have a large button at the joint / connection point to the throttle assembly which engages and disengaged the forward and reverse bucket (so you can rev up the engine without putting the boat in gear so to speak)? See the black disc in the attached pic. Also make sure that the control rod is attached to the top of the bucket.

Thanks, I will check that...not sure if my boat have that black disk. the issue is that randomly some times it engae and most of the times I tried it didn't engage to provide propulsion while the RPMS goes up

 

[JC Chile]

Need pics of the pump and impeller to diagnose better. Take pics looking into the pump with the hood in full forward.

Seems likely that you bent the impeller blades slightly or you caused damage to the wear ring.

will take pics to share, Thank you so much for your help

 

[ZippyBoater]

yes, there is some damage on the impeller but it didt seams to bi that big. i will take better pics to share but this is what i have now

That kind of damage will cause cavitation, but you should be able to move. Acceleration will be slow, but you should be able to get up to speed. You may want to check the tunnel that the water flows through for damage.

 

[JC Chile]

Did you put the clean out plug all the way back in? If so, I'd pull the pump off the back to look for additional stuff wrapped around the shaft. Should take you 15 minutes to do, and is very easy (5 bolts and one quick release on the reverse gate).

Thanks! I already took the pump out and it was clean.

 

[JC Chile]

That kind of damage will cause cavitation, but you should be able to move. Acceleration will be slow, but you should be able to get up to speed. You may want to check the tunnel that the water flows through for damage.

Thanks ,I will check that again...on my first inspection it didn't seems to have damage on the tunnel

 

[Cobra Jet Steering LLC]

Do the splines on the end of the driveshaft look good and can you turn the drive shaft with your hand and the impeller also turns? if so that isn't the problem. However there is a coupler on the intermediate bearing where the splines slide in that may be stripped

 

[84rzv500r]

that impeller will cavitate bad... with a single engine boat there is no second pump to get you moving and help get water through the bad pump... order a new impeller and hang that one on your your wall or send it out for repair... inspect the wear ring for scoring groves or damage and replace as required...

 

[JC Chile]

The cavitation makes sense...my only doubt is why when I was testing sometimes works well and others get loos and loos propulsion.

 

[JC Chile]

Do the splines on the end of the driveshaft look good and can you turn the drive shaft with your hand and the impeller also turns? if so that isn't the problem. However there is a coupler on the intermediate bearing where the splines slide in that may be stripped

will check the splines with more detail Thanks!

 

[84rzv500r]

The cavitation makes sense...my only doubt is why when I was testing sometimes works well and others get loos and loos propulsion.

well if you were moving even a couple of mph or were careful and slow giving it throttle you can prolly nurse it to move...

this is the junk stator on my stbd engine it cavitates horribly if i don't trail the port engine on throttle up... see the missing chunks of stator veins? once I'm moving above like 30 mph it kind of works... but t thrust is low... and it will barely move if i just use that engine... in contrast the port engine will get the boat on plane with the starboard engine idling

I built new prototype pumps but I wont have all the parts to install till thursday///

 

[JC Chile]

WOW! well, it seems that cavitation could be my problem...thanks for the guidance