Mercruiser 165 no power under load

[nawlinjoe]

Guys I need some help. I have a rebuilt mercruiser 165 that I put in the water today and wouldn't go over 1700 rpm's.<br /><br /> The motor starts and idle fine but, boggs down when I give her power . The motor has 99% new parts including a auto distributor. Someone told me that the distributor may be the problems.

 

[FENIXX3435]

Re: Mercruiser 165 no power under load

I had the same issue, Distributor wasn't advancing. But I also had a fuel delivery problem also Good luck!

 

[DHPMARINE]

Re: Mercruiser 165 no power under load

The distributor is a problem.It could be dangerous.but beyond,or before that think about it.In a car,you idle,increase speed a bit,slow down a bit,increase speed a bit,open it up,hit the brakes a bit.<br />In your boat you open it up and get on plane.You slow down and get a skier,and do the same thing again.<br />Distributors have advance curves (weights).<br />I doubt the automotive is the same as marine,and won't run well.<br />I'll let others tell you about the explosion factor,but don't worry,a boat only burns down to the waterline,if one is left.<br />Joe,I'm just having fun here,but read these posts.There is a world of knowledge to be had.<br /><br />DHP

 

[nawlinjoe]

Re: Mercruiser 165 no power under load

Yeah I know I should use a marine distributor. But what puzzle me is that the engine revs high when I give it throttle but the boat doesn't move untill I back off the throttle.

 

[Don S]

Re: Mercruiser 165 no power under load

Originally posted by joe99:<br /> Yeah I know I should use a marine distributor. But what puzzle me is that the engine revs high when I give it throttle but the boat doesn't move untill I back off the throttle.

In your first post you said you could only get to 1700 rpm's, or is that where it starts reving and not moving or slowing down.<br />May be a spun prop hub or bad engine coupler if you are gaining rpm and loosing boat speed.

 

[nawlinjoe]

Re: Mercruiser 165 no power under load

Yes it does get up to 1700 before the motor slows down. How could I check to see if its a spun coupler?

 

[jimmythekid]

Re: Mercruiser 165 no power under load

Originally posted by joe99:<br /> Yeah I know I should use a marine distributor. But what puzzle me is that the engine revs high when I give it throttle but the boat doesn't move untill I back off the throttle.

sounds like a spun hub in the prop

 

[ziggy]

Re: Mercruiser 165 no power under load

joe, i don't understand.<br /> <br />"The motor starts and idle fine but, boggs down when I give her power ."<br /><br /> "But what puzzle me is that the engine revs high when I give it throttle but the boat doesn't move untill I back off the throttle."<br /> <br />"Yes it does get up to 1700 before the motor slows down."<br /><br />so it boggs down when reved to 1700, then ya back off and it slows down. don't sound like it's reving too much. i'm not a mechanic like some of these guy are. but i'd sure suspect the distributor. not to be to blunt, but i'd get a marine distributor. auto parts are not made for marine use. ya really don't want to burn do ya? might just make it run better too. what dhp had to say about the advance curve of a marine dist. vs. a auto dist. makes sense too. also, i got a 165 too and i had a fuel filter that pluged on me. only allowed about 3500 rpm till it got real pluged, then only let me idle, barely got home that day. new fuel filter and i was hip. hope it's the dist. for ya. bet that's easier to replace than the coupler dons is talking about.

 

[nawlinjoe]

Re: Mercruiser 165 no power under load

Thanks guys for all the replies and I will be installing a Marine Distributor soon. As for the spun prop/ coupler when I installed the motor I did notice that the coupler was in good shape.<br /><br />The motor prior the rebuid didn't had that many hours and had seized due to winter damage. <br /><br />I'll see what happens when I install the distributor

 

[trapped]

Re: Mercruiser 165 no power under load

I don't know if this would be the same problem, but I have a 165 in my '75 Century. When it's cold (under 50 or so for me) it will bog like you have described. Once it warms up its good to go. I suspect that I need to go through and adjust the carb mixture settings. All stock parts, marine distributor, etc.