new member

[kdwjohnson]

Hey guys, i'm new to boating and this forum. I really enjoy and have learned a bunch from the Q&A's. I have a 90 model 26' bayliner w/305 mercruiser(chevy) motor and a mercruiser outdrive. I bought it used end of last summer and used it a few times before winter. I live in central Louisiana. I was having a problem with it overheating, around 180, sometimes climbing towards 200. I could play with the trim and keep it around the 180 deg mark. I read this forum looking for answers. tried everything from replacing lower unit pump, pulling exhaust and boiling them out, changed circulating pump, termostat & checked ps cooler for pluggage, and found nothing. Finally felt around the gimbal ring/housing and found a kincked water intake hose. Read next to impossible to change without pulling gimbal ring, but I did it. Now my temp is 155 deg constant. Only problem is it runs great at first, and then after a little bit looses power. Starts out at 4000+ rpm wot and 31 mph but drops to 3300 rpm & 24 mph. Any suggestions? Also what is the elbow fitting on the distributor cap for? thanks for any help.

 

[orion25]

Re: new member

Hey guys, i'm new to boating and this forum. I really enjoy and have learned a bunch from the Q&A's. I have a 90 model 26' bayliner w/305 mercruiser(chevy) motor and a mercruiser outdrive. I bought it used end of last summer and used it a few times before winter. I live in central Louisiana. I was having a problem with it overheating, around 180, sometimes climbing towards 200. I could play with the trim and keep it around the 180 deg mark. I read this forum looking for answers. tried everything from replacing lower unit pump, pulling exhaust and boiling them out, changed circulating pump, termostat & checked ps cooler for pluggage, and found nothing. Finally felt around the gimbal ring/housing and found a kincked water intake hose. Read next to impossible to change without pulling gimbal ring, but I did it. Now my temp is 155 deg constant. Only problem is it runs great at first, and then after a little bit looses power. Starts out at 4000+ rpm wot and 31 mph but drops to 3300 rpm & 24 mph. Any suggestions? Also what is the elbow fitting on the distributor cap for? thanks for any help.

What size prop is on it? You should be getting more than 4000 rom WOT.

 

[kdwjohnson]

Re: new member

The info on the motor and manual says 4200-4600 wot. The prop is a 16x16 and I had it reworked and repitched to a 16x15. I talked to a mercruiser rep and he also said it should be a 16x16. I believe I need to go down another inch in pitch. But that doesn't explain why it starts off good and then drops about 1k rpms after it runs a little while.

 

[HT32BSX115]

Re: new member

Howdy,

Before you bend your prop some more you might need to ensure that you're tuned up correctly, compression is ok, and you have an accurate tach. Some tachs can be way off at the top end of the scale.

Use a GPS to verify your speed.....and oh, make sure you're not either waterlogged or the bottom is covered with critters and other growth!


Cheers,

Rick

 

[kdwjohnson]

Re: new member

I checked my tach with a strobe light from work but not on the top end. I'll get it and do it again at wot. The speed is with a gps. I did clean the bottom, but i'm sure it could be better. But do you think that would have anything to do with it running good at first and then losing power after a while? What about the small fitting on the distributor cap? I ordered a new distributor and rotor and it also came with the small fitting on the cap. It screws into the cap and has a barb on the other end like for a hose maybe. Or could it be just a vent to keep down condensate?

 

[Pierutrus]

Re: new member

I checked my tach with a strobe light from work but not on the top end. I'll get it and do it again at wot. The speed is with a gps. I did clean the bottom, but i'm sure it could be better. But do you think that would have anything to do with it running good at first and then losing power after a while? What about the small fitting on the distributor cap? I ordered a new distributor and rotor and it also came with the small fitting on the cap. It screws into the cap and has a barb on the other end like for a hose maybe. Or could it be just a vent to keep down condensate?

It's a heat problem.
Have never checked my tach with a strobe/timing light. What good would that do?
Something is heating up and breaking down.....
I'm thinking, the "COIL".
Replace it.

 

[kdwjohnson]

Re: new member

Good point. I have bought a new coil and will install before going out again. The strobe light I'm referring to is a rpm strobe for checking rpm on rotating equipment like pumps amd blowers, not a timing light. I'm a reliability tech and perform analysis on equipment in the plant where I work. What about the fitting on the distributor cap?

 

[Pierutrus]

Re: new member

Good point. I have bought a new coil and will install before going out again. The strobe light I'm referring to is a rpm strobe for checking rpm on rotating equipment like pumps amd blowers, not a timing light.

Guess what. A distributor is rotating equipment. You might be getting weak spark from the coil after it warms up.

As far as the fitting on distributor.....ie..you don't mean the spot where you set the dwell do you?

 

[Bondo]

Re: new member

Starts out at 4000+ rpm wot and 31 mph but drops to 3300 rpm & 24 mph. Any suggestions? Also what is the elbow fitting on the distributor cap for? thanks for any help.

Ayuh,.... That's the Vent on the distributer.....
Sparks can Not go around a Corner,... hence the Fitting.....

As for the drop in rpms,..... Have you changed the Fuel Filter lately,..??

 

[kdwjohnson]

Re: new member

Yes I have. I'm doing a complete tune-up. Changing the distributor cap, rotor, and ignition sensor, and plug wires. This boat has been setting up and not really maintaned like it should. I also pulled the little filter going into the carb but it didn't look dirty, but cleaned it and re-installed. So between all this, I hope to put it back on the water sometime this weekend. I'll let you know how it goes. Thanks for all the imput.

 

[whywhyzed]

Re: new member

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