Mercury model 1150 thunderbolt 115hp - Power Cut while running

[mikesboat]

My mercury model 1150 thunderbolt 115hp was running fairly well all week. A couple of times it sounded as though it was going to stall while running, had someone squeeze the ball & it would be fine again while running. Last day of the week, it would completely die while running without warning, just quite...always started again, but would quite again after a couple hundred yards. Any ideas on the problem...suggestions?

 

[Dave1027]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

If squeezing the bulb temporarily fixes it then it's probably the fuel pump.

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

Do you suggest replacing the fuel pump? I've heard others just replace the diaphragm??? I also have low compression in the #1 cylinder.

 

[Chris1956]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

Mike There are rebuild kits for the fuel pump. I recommend you install one. How low is the compression on your cylinder? What are the other compression numbers?

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

#1 Cyl is at 20psi - other 5 cyl. avg 115psi - 120psi. Will try the Fuel Pump rebuild kit, have had that same recommendation from others as well.

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

Purchased a Fuel Pump rebuild kit & a new, better quality, primer bulb. going to replace both today & put the boat in the water tomorrow. Replacing the primer bulb with the suspicion that the current one has developed an air leak or has a bad valve. hoping for the best tomorrow!

 

[njrextreme]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

20 on # 1, yikes. I hope its not a bad cyl. or piston.

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

we're not sure which it is either. i have a mechanic that is either going to rebuild or replace the powerhead this winter. we've owned the boat for 5 years, thinking that it has always been low on compression & never knew it. when it's not cutting out on us it runs like it always has...at least as long as we've owned.
what type of mph do you suppose that we should achieve with the 115hp on an 18' Glastron Tri-Hull? depending on the water conditions, we'll top out around 28-31mph.

 

[njrextreme]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

we're not sure which it is either. i have a mechanic that is either going to rebuild or replace the powerhead this winter. we've owned the boat for 5 years, thinking that it has always been low on compression & never knew it. when it's not cutting out on us it runs like it always has...at least as long as we've owned.
what type of mph do you suppose that we should achieve with the 115hp on an 18' Glastron Tri-Hull? depending on the water conditions, we'll top out around 28-31mph.

How much is the weight w/ fuel and passengers? My boat is close to 16 foot glass-dry weight 750 ,so under 1500 loaded w/ a couple guys. It had a Mariner 90 I-6 and I could get close to 50mph on a perfect day. Now it has a merc 115 but older so 90 hp at the prop, and still pending my first water test w/ the diff. motor. I would expect it will be close to the same. I will find out very soon.

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

used the rebuild kit for the fuel pump & replaced the primer bulb...still has the same issue today. one time the motor even had a very violent shutter, almost stalled out & then kicked back up again. could not keep it running for a long period of time if the RPM's were above about 2400. Could it be the carbs? should they be cleaned/rebuilt? what's a good source for "how to" step-by-step for the carbs?
thank you in advance for your help!!!

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

Any advice &/or direction regarding cleaning the carbs would be greatly appreciated.
Thanks.

 

[mikesboat]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

...

 

[John D Terry]

Re: Mercury model 1150 thunderbolt 115hp - Power Cut while running

check to seee if your fuel bulb flattens out when it dies, if so your tube in your gas tank has a screen in it and is clogged. Remove it after you clean your gas tank.