Engine Help

[Tracy Strickland]

I need some info from you experts...I have a 1996 Nitro 185FS with a 90hp Merc. when I got it 4 years ago the top speed was less than 10mph. it had been sitting and we thought it was the gas/carbs. it turned out not the case. now it is doint it again but before I tell you what we fixed the first time I was wondering what you guys thought now. it will rev in nutreal to 7,000rpms with no problem. under a load I truly believe I can swim faster and it wont pull itself up on the trailer. I replaced the spark plugs 3 times this past weekend, new fuel filter, gas line had a small leak, sea foam in the fuel. I did not stabilize the fuel last year cause it was almost empty. a guy at the dock said I was sucking air when putting it on the trailer. the bulb will keep gas in it but not completely firm so I am going to replace that with the fuel hose. any other suggestions. plugs look fine but have not tested spark but I think it is ok based on the plugs.

 

[Larry Harp]

I've told this story here before but I'll be happy to tell it again...



My old PT-185 had a 50 horse Merc. For no known reason It started doing something similar to what you are describing. It would rev freely but when in gear and trying to go somewhere it wouldn't pull

Granny out of her rocking chair. It would do this inconsistantly. Sometimes it would do it first thing in the morning and then start running fine later. I first drained all the gas and replaced it with fresh gas and a dose of Quikleen. That didn't help. I took it to the dealer where they R&R'ed the carbs for somewhere around $250. The day I picked it up I took it to a local lake and it ran like a turpentine cat. Next time to the lake for some real fishing and it was the same ol crap. Went back to the dealer and the service manager gave me a new fuel bulb. I put that on and it fixed it. It ran great after that. I remember someone here, either Toxic or Neeley, saying that they didn't give me a free fuel bulb... it cost me $250.:lol: A couple of years later the motor started to cut out at full speed. Remembering my past experience the first thing I did was change the bulb. That fixed that. So, it is my opinion that the first thing to do whenever the motor isn't running right is to change out the cheapest thing, the fuel bulb, first. It may not fix it but at least you'll know it's not the problem.

 

[Dan J.]

Check the ignition/run voltage for a defective stator. It will create the symptons described as well as the aforementioned. Good luck!

 

[Mike Tosello]

Sooner is right on..... Replace the fuel bulb first, it'll be your cheapest fix and alot of times is the cause of many problems....



Mike

 

[Tracy Strickland]

well the bulb is exactly what I am thinking. the last time I had this problem my mechanic said he adjusted the throttle linkage. it makes sense to me but I have been told by many that he lied to me. I do know he fixed it in less than 10 minutes and didnt charge me but $10. the bulb is not holding fuel like it should and one guy told me I was sucking air. in my younger days I would have hit him real hard! but now I am wiser and figures he was only trying to help. I am also going to check the compression on monday. any ideas what it should be??



as far as the stator issue I am not the best mechanic in town and I really dont even know what that is.....

 

[Drew Dennis]

If you keep reving it to 7000 rpm you wont have to worry about speed...you will blow it to heck and back. They are NOT desiged to be "free revved" like that. ESPECIALLY if you are doing it out of the water and on the muffs. No backpressure on it and revving it like that could very well cause a "runaway" engine that you CANNOT turn off. at that point all you can do is starve it for fuel to kill it and pray you didn't damage it.



That being said, have you checked to see if you have a spun prop?

 

[Tracy Strickland]

I have only revved the engine to 7,000 rpms twice in the water and only for a second just checking it out. However, this boat does run around 6,000 rpms normally at full speed. I have not pulled the prop but I did notice the nut keeper is on backwards. not sure why because the prop has not been off since I had the lower unit replaced 2 years ago by a boat mechanic.

 

[TOMMY RICH]

5500 is max

 

[Tracy Strickland]

5500 is max meaning that is all it will do or all you should do? cause it does alot more! :huh:

 

[TOMMY RICH]

All you should do...with the right(wrong) prop...it go BOOM!

 

[Tracy Strickland]

but I have this need for speed!

 

[Larry Harp]

but I have this need for speed!

You're going to have a need for a new motor if you keep on over revving it.:lol::lol::lol:

 

[Dan J.]

I am also going to check the compression on monday. any ideas what it should be??

Around 100psi min. to 110. It's give or take on an older powerhead. Most importantly, make sure the cylinders don't vary by a couple pounds compression. Even wear is what you're wanting to see.



Have you checked for the previously mentioned spun hub on your prop? A lot of slip will create some of the performance issues you state. Put it in gear on the trailer with the key off and see if the prop will break away, turning by hand. If it does, you'll need to press in a new hub. (See any prop shop.) Sitting for a long time will cause this to dry rot.



Additionally, check your tach for accuracy....and your GPS. (Forget about your speedo. They are notoriously inaccurate.) The stats you've mentioned in your posts (mid 50's) with that hull are possible with a 3 cyl., but normally found with the aftermarket addition of a demand valve and a little hose attached to the carbs going to a small bottle of NO2.:lol:



Seriously, after checking fuel delivery, check the stator start/run voltage as well. It's located under the flywheel. (I believe it's tan for ground, one blue, and one purple w/pink tracer pos. leads)



Boats that sit for extended periods can easily have multiple issues creating a cascade effect. (Hopefully not.) You should really consider biting the bullet and having a good marine mechanic look it over. Either way good luck!

 

[Scott Hammer TOXIC]

Ditto what big Dan advises. I have a linkage problem and most could fix but I don't feel comfortable messing with my shift linkage. Cable stretch according to my mechanic. Its going to the shop!!



TOXIC

 

[Tracy Strickland]

Around 100psi min. to 110. It's give or take on an older powerhead. Most importantly, make sure the cylinders don't vary by a couple pounds compression. Even wear is what you're wanting to see.



THANKS



Have you checked for the previously mentioned spun hub on your prop? A lot of slip will create some of the performance issues you state. Put it in gear on the trailer with the key off and see if the prop will break away, turning by hand. If it does, you'll need to press in a new hub. (See any prop shop.) Sitting for a long time will cause this to dry rot.



NO I HAVENT HAD TIME BUT I ALSO DID NOT KNOW I COULD DO IT AS YOU STATED.



Additionally, check your tach for accuracy....and your GPS. (Forget about your speedo. They are notoriously inaccurate.) The stats you've mentioned in your posts (mid 50's) with that hull are possible with a 3 cyl., but normally found with the aftermarket addition of a demand valve and a little hose attached to the carbs going to a small bottle of NO2.



THE GPS WAS NOT MINE A FRIEND DID IT AND IT WAS RIGHT WITH THE SPEDO. AND NO NO2.....

Seriously, after checking fuel delivery, check the stator start/run voltage as well. It's located under the flywheel. (I believe it's tan for ground, one blue, and one purple w/pink tracer pos. leads)



OK



Boats that sit for extended periods can easily have multiple issues creating a cascade effect. (Hopefully not.) You should really consider biting the bullet and having a good marine mechanic look it over. Either way good luck!



MY PROBLEM IS THE ONLY GOOD BOAT MECHANIC IN MY TOWN MOVED TO TEXAS! HE IS THE ONE WHO FIXED IT LAST TIME AND HE SAID IT WAS THE THROTTLE LINKAGE. FIXED IT IN LESS THAN 10 MINUTES FOR $10. THE REST OF THE MECHANICS HERE ARE PART REPLACERS!!![/b]

 

[Tracy Strickland]

Ditto what big Dan advises. I have a linkage problem and most could fix but I don't feel comfortable messing with my shift linkage. Cable stretch according to my mechanic. Its going to the shop!!



THIS IS EXACTLY WHAT I THINK THE PROBLEM IS ALONG WITH THE BULB SUCKING AIR. BUT, OUT OF GEAR IT SEEMS TO BE WORKING CORRECTLY AND IN GEAR IT HAS NO POWER. ALSO, WHEN SHIFTING WITH THE BOAT OFF THE LINKAGE ON THE MOTOR SEEMS TO BE WORKING CORRECTLY. DOES ANYONE KNOW WHERE THE ADJUSTMENT SHOULD TAKE PLACE?

 

[Tracy Strickland]

ok so I think I have my engine problem solved (well I cant really tell cause with all the rain in Indiana all the boat ramps are closed so I cant check it). I had an air leak in the fuel line from the tank to the bulb. now I have fuel in the filter!

 

[Tracy Strickland]

ok so it is still not working. just put it in the water after fixing the air leak. I do have fuel in the filter. when I give it full throttle it bogs down and dies. had it running with the air lid off and put in carb cleaner. it did not make a noticible difference. prop is not spun. it kinda reminds me of my riding lawn mower when I have the choke on and it dies....



what exactly can I check on the stator?



we are wanting to leave on Tuesday with it again for Barkley Lake. Thanks for the input.

 

[Tracy Strickland]

its FIXED!!!!



it turns out the bottom of the 3 carbs was gummed up a little! but the little stuff I fixed needed to be done also. found a great mechanic here through a referral so if you are in southern indiana I can help! $65 to take it off and clean it out but I gave him $80 cause I just called him this morning and he got me in today and my son left with the boat around 3. Great Service!!



thanks for all the suggestions and to be honest everyone was right on with suggestions cause he checked everything you suggested first.....