Merc 350 running hot - impeller??

[JJGraham00]

Hello all,<br /><br />I have a 1989 Regal with a Mercruiser 350 in it. The past couple of times I have been on the water I have noticed the engine is running hot after a few minutes in the no wake zones. I have found that letting the engine run at ~2000 RPM for a few seconds brings the engine temp back under control. I was thinking this was probably one of the impellers...but thought I would bounce it off this group first. Does this sound like an impeller? If so, about how expensive a fix is this??<br /><br />Thank you for any help or suggestions you guys can provide!<br /><br />Regards, <br /><br />Jeff

 

[lenny2113]

Re: Merc 350 running hot - impeller??

Jeff,<br />When was the last time impeller was changed?<br />It is a good practice to change it every season.<br />I would start with impeller.<br />If you trailer your boat, it will be easy for you to do. You may want to try fixing it yourself. If that's what you want to do, do a search in this forum on "impeller". You should find a link to give you a complete instruction.<br />If you let marina mechanic do it it should not be more then $150 + $60 parts.<br />If you don't find link to instructions and would want to do the replacement yourself, I will post the link. Just need to find one myself.<br />Mercruiser OEM manual is the best thing for repairs reference.<br /><br />Good luck,<br />Lenny

 

[JJGraham00]

Re: Merc 350 running hot - impeller??

Thanks Lenny!<br /><br />I will work on replacing that impeller this weekend.<br /><br />Regards,

 

[crazy charlie]

Re: Merc 350 running hot - impeller??

Jeff,my guess is that the problem is not the impeller but dont let that stop you from replacing it.You can never make a mistake by changing an impeller if it is more than a year or two old.Because the temp comes down when the rpms go up means that the impeller is working.The manifolds or risers may be a little clogged or ready for replacement.There is also a circulator pump on the front of the motor that can be in need of changing.Charlie

 

[JJGraham00]

Re: Merc 350 running hot - impeller??

cool. If the ipeller does not help me I will check out the manifolds / risers. How big a job is this?<br /><br />Thanks guys....

 

[crazy charlie]

Re: Merc 350 running hot - impeller??

which Regal do you have????If it is a 255 ambassador you have it made,plenty of room to work and not too tough of a job.Charlie

 

[JJGraham00]

Re: Merc 350 running hot - impeller??

Its a 22' Valanti CC. Sometimes it seems a bit cramped, but not too bad to work on (I do not have alot of experience on other boats though). <br /><br />Hoping to get this overheating problem knocked out today....<br /><br />I am actually trying to sell it. Any advice on where to advertise?

 

[JJGraham00]

Re: Merc 350 running hot - impeller??

OK guys... so I was able to get the impeller in last night and all seemed to be well. It appears that this solved my overheating problem. However, I think I may have messed something up with my gears. When the engine is in neutral my prop is spinning (not just slowly spining from vibrations... it is being driven). When I rev the engine (still in neutral, the prop spins faster) When I attempt to put the thing in gear... it stalls. I am assuming I missed something here? Any advice on where my problem may be?<br /><br />THANK YOU!

 

[rattana]

Re: Merc 350 running hot - impeller??

Before reassembling the upper and lower you have to ensure the lower unit is in forward gear and the shift shaft for the upper is pointing straight forward. Two people make this much easier. You may have to put some slight pressure on the prop to hold it in forward while mating the two halves together.

 

[crazy charlie]

Re: Merc 350 running hot - impeller??

Hopefully you are referring to a manual while doing this.If you are not the chances of getting it right the first time are very slim.Did you remove the drive from the boat or just the lower unit???? Charlie

 

[JJGraham00]

Re: Merc 350 running hot - impeller??

Lesson learned...Follow the instructions. Thanks for your help all. I think I am in good shape now... had to take that friken lower unit off three times this weekend, but she runs good now!!!! My overheating also seems to be under control. <br /><br />Take Care <br />Jeff